427 Problems

427 Problems

Bill
Bill

June 4th, 2006, 6:45 pm #1

Does this sound familiar to anyone? I have a 427 that runs like a champ while it's dry docked, and I can run it for 10 minutes at 4200 rpm on the lake, and then it misfires and quits as if it ran out of gas or had a major vapor lock. It wont restart until the engine cools down. The engine hadn't been run since 1999. I took advice from three different mechanics who had three different opinions and it still does the same thing. My interpretation is it acts as if it takes awhile to get up to temperature and once it does it cuts out. I thought possibly a water or a choke problem. I installed a new main water pump and ran it to no avail and was told it was the coil. I replaced the coil and at the same time I replaced the thermostat. When I ran it again it overheated missed and died again. Any thoughts?

This is what I have done in order:

1) Drained the fuel
2) Installed new fuel pump
3) Installed new impellar
4) Installed new fuel filter
5) Rebuilt the carb
6) Timed
7) Test drive (limped in on other engine)
8) Installed new water pump
9) Drained fuel
10) Installed new plugs
11) Installed new hoses
12) Checked points
13) Test drive (limped in on other engine)
14) Installed new coil
15) Installed new thermostat
16) Test drive (limped in on other engine)
17) Found this site

Any suggestions would be appreciated.




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Dave Mehl
Dave Mehl

June 4th, 2006, 7:30 pm #2

I don't own the 427 but I sure have enjoyed reading the diagnostics from a variety of people who do, and they've been all over the motors from stem to stern. Lots of what is written will apply to all motors of the era, so I have printed numerous issues for my files.

I will start by offering a thought about your ignition system. If you run for 10 minutes and then the motor chokes off and won't run or start, I would IMMEDIATELY pull a wire, hold it 1/4 inch away from the plug and have someone rotate the starter to see if you have any spark at that point. If you do, then you can eliminate ignition from the list.

Another thought is a "heat induced" issue, where a gasket in the intake system may be loose or improperly fitted. Any gap there will cause odd running conditions. Here are some files I've bookmarked to help me diagnose similar problems with my Lincolns. The first thread is actually about a Chevy, but the same thing can apply to the big motors too.

http://www.network54.com/Forum/424840/m ... 1143830136

http://www.network54.com/Forum/424840/m ... 1142024932

http://www.network54.com/Forum/424840/m ... 1138021506

http://www.network54.com/Forum/424840/m ... 1127490846

It may take a few days to hear back from everyone, but Curt had lots of debris in his tank (see photos), Paul spoke of clogged lines leading to the fuel pump, Mark had ignition problems at the distributor, and the list goes on. After a few bent pushrods and carb rebuilds, as far as I know all the 427s on the forum are running like champs. Hope this helps get you started.

Regards,

Dave Mehl


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Paul
Paul

June 4th, 2006, 10:31 pm #3

Does this sound familiar to anyone? I have a 427 that runs like a champ while it's dry docked, and I can run it for 10 minutes at 4200 rpm on the lake, and then it misfires and quits as if it ran out of gas or had a major vapor lock. It wont restart until the engine cools down. The engine hadn't been run since 1999. I took advice from three different mechanics who had three different opinions and it still does the same thing. My interpretation is it acts as if it takes awhile to get up to temperature and once it does it cuts out. I thought possibly a water or a choke problem. I installed a new main water pump and ran it to no avail and was told it was the coil. I replaced the coil and at the same time I replaced the thermostat. When I ran it again it overheated missed and died again. Any thoughts?

This is what I have done in order:

1) Drained the fuel
2) Installed new fuel pump
3) Installed new impellar
4) Installed new fuel filter
5) Rebuilt the carb
6) Timed
7) Test drive (limped in on other engine)
8) Installed new water pump
9) Drained fuel
10) Installed new plugs
11) Installed new hoses
12) Checked points
13) Test drive (limped in on other engine)
14) Installed new coil
15) Installed new thermostat
16) Test drive (limped in on other engine)
17) Found this site

Any suggestions would be appreciated.



Hello Bill,

Welcome to the forum! Were going to find the problems with your boat, its just a matter of time.

Whatever the issue, it appears to be ancillary in nature and not "main mehcanical". Many old boat owners are so rattled at ancillary malfunctions, they end up getting hooked for tens of thousands of dollars worth of repowering, when all it really is may be the need for attention to detail and careful troubleshooting.

On one of my 427s, I got a zero compression in one cylinder, because the prev owner had set the valves so poorly. He didn't know what the heck he was doing, quite frankly. Once set properly, compression came up and the motor is still running great ten (10) years later. A 427 does not like to run if the valves are set too tight. Too loose, it will run, and make lots of valve noise, without developing full power. Set right, they're just beautiful.

Sooner or later you'll want to upgrade to the PERTRONIX ignition modules, there is a dedicated thread on this, and it's simple and cheap, and the benefits over running a 427 with ignition points are immense. Many 427 owners have done this.

Youve got a lot of issues with an engine that has not been run since 1999. Many times, well see more than one gremlin working at the same time. Dont assume its just one thing.

In your last comment, you said the engine overheated, missed, and died again. Question that needs to be outlined for me and the others who will want to comment, is the overheating a normal thing, does it overheat and then stall out, or did it just overheat this particular time? Also, what was the nature of the overheating, how hot did it get, did it make any special noises, etc.?

Also, have there been any mods to your motors? Are you running stock PCV valves, ballast resistors, and carbs? Did the boat once run well, and now is it acting up? Is this a raw water cooled motor, or do you have heat exchangers with antifreeze in the reservoir?

Are you running ballast resistors and the proper coils? If not, the coils may well be overheating and getting so hot theyre losing their ability to generate a spark and then fail. Changing to a new improper coil may just replicate the old problem. I think Dave had a good comment, when you lose power, do you actually have any spark? Need to know this (good comment Dave!).

Dave had another good comment, and thats the heat induced vacuum change. Its possible that the hot engine causes something to loosen up and admit more air below the carb somewhere in the intake system. The carb may be loose, the gasket may be admitting air under the carb.

My first guess, however, is obstruction within the fuel lines. It sounds like the engines run long enough to draw debris into an obstruction and then they choke out. Curt Hill had similar issues to yours and he found he had a lot of junk in his tanks. I have a buddy here in Nashville with a much newer boat, and he would run down the river several miles and every trip (when the engines got hot) he would stall out at the same general location. He thought it was the Bermuda Triangle of the Cumberland. He tried everything, but found eventually after changing out lots of parts, it was an obstruction that occurred at an anti-siphon valve in his fuel line. We old boat owners dont have anti siphon valves, but we do have shut off valves with 90-degree bends, etc. He finally found out he could run down the river for a while until particles finally built up enough to stall out his motor. Sounds just like yours.

Someone on the forum suggested hooking a temporary test fuel line to an outboard motor fuel tank, running off it to be sure your main tanks were not the issue. Doing so would guarantee you were getting a clean and unobstructed fuel supply. I suggested to Curt, that he hook up a suction to his fuel lines and pull out whatever it was down there, to test if it was a continual fuel supply. He changed out filters, etc., but finally found lots of debris was clogging his main flow to his fuel pumps. He pulled his pick-up tubes, and siphoned out lots of debris.

I would hope Tim Toth, Mark Weller, and Curt Hill, among others, Tom, Dave, Howard, Wes, would offer their comments too to help diagnose your issues. What we need are as many symptoms as possible.

For instance, when you tried to restart, did you look into the carb (with the motor off), and pump the throttle to see if you were getting jets of fuel squirted into the carb? If so, fuel starvation probably is not the issue. If you can see fuel squirting when you run the throttles all the way forward and back, and if youre getting a spark as Dave noted, then were ready to solve the problem, as theres not a whole lot of issues left.

I would wonder if when your engine stalls out, if it would restart and run if it was given a boost with starter fluid. This is not normally such a good idea, but starter fluid will make a motor start under just about any condition, vapor lock or not. I wouldnt recommend this, because I would satisfy my curiosity by checking for spark when the motor cuts off (as Dave recommended) and then Id look into the carb and see if it was overly wet (over choked) and also have someone pump throttles to see if you are able to see fuel being squirted into the carb. If you see fuel being squirted, I doubt if starvation is the issue.

Fuel pumps may be suspect. Malfunctioning choke may be suspect too. When you stall out, pull the flame arrestor off, look inside, and if you see the choke butterfly closed, the heat activated choke mechanism may be malfunctioning.

Here is a thread to Curt Hills sawdust in the tanks thread.
http://www.network54.com/Forum/424840/m ... 1146731677

Regards, all the best, gimme some help here fellas!

Paul

















Last edited by FEfinaticP on July 9th, 2009, 2:19 pm, edited 1 time in total.
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Steve
Steve

June 5th, 2006, 1:41 am #4

Does this sound familiar to anyone? I have a 427 that runs like a champ while it's dry docked, and I can run it for 10 minutes at 4200 rpm on the lake, and then it misfires and quits as if it ran out of gas or had a major vapor lock. It wont restart until the engine cools down. The engine hadn't been run since 1999. I took advice from three different mechanics who had three different opinions and it still does the same thing. My interpretation is it acts as if it takes awhile to get up to temperature and once it does it cuts out. I thought possibly a water or a choke problem. I installed a new main water pump and ran it to no avail and was told it was the coil. I replaced the coil and at the same time I replaced the thermostat. When I ran it again it overheated missed and died again. Any thoughts?

This is what I have done in order:

1) Drained the fuel
2) Installed new fuel pump
3) Installed new impellar
4) Installed new fuel filter
5) Rebuilt the carb
6) Timed
7) Test drive (limped in on other engine)
8) Installed new water pump
9) Drained fuel
10) Installed new plugs
11) Installed new hoses
12) Checked points
13) Test drive (limped in on other engine)
14) Installed new coil
15) Installed new thermostat
16) Test drive (limped in on other engine)
17) Found this site

Any suggestions would be appreciated.



There is a wealth of info. always posted from some people well versed in engine mechanics and troubleshooting.....and I'm not one of them. With that being said, I had a similar problem many years back with a 327 in my 31' Commander. The engines always started and ran well until about a half hr. into the cruise(app. 2900RPM).Then the starboard motor would sputter and quit and not re-start and I'd limp back to the dock on the port motor.I made a list to replace of all the usual things that one would suspect could cause the problem.Halfway through the list, the problem kept rearing its ugly head,except once when it occured at dusk.I didn't know it at the time, but some of the cabin lights that were on had gone out.Again, we limped back to the dock with one motor,which took about an hour.Just as we tied up for the night,my wife said "the cabin lights just went back on".Hmmm. The next day, I pulled out the wiring diagram and to make a long story short, I cleaned and re-tightened all the connections to the terminal block located on the rear of the engine and I never had that problem again in the eight years that I owned the boat.For what it's worth, sometime the problem is real simple. Good luck and best regards,
Steve
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Bill
Bill

June 5th, 2006, 4:20 am #5

I don't own the 427 but I sure have enjoyed reading the diagnostics from a variety of people who do, and they've been all over the motors from stem to stern. Lots of what is written will apply to all motors of the era, so I have printed numerous issues for my files.

I will start by offering a thought about your ignition system. If you run for 10 minutes and then the motor chokes off and won't run or start, I would IMMEDIATELY pull a wire, hold it 1/4 inch away from the plug and have someone rotate the starter to see if you have any spark at that point. If you do, then you can eliminate ignition from the list.

Another thought is a "heat induced" issue, where a gasket in the intake system may be loose or improperly fitted. Any gap there will cause odd running conditions. Here are some files I've bookmarked to help me diagnose similar problems with my Lincolns. The first thread is actually about a Chevy, but the same thing can apply to the big motors too.

http://www.network54.com/Forum/424840/m ... 1143830136

http://www.network54.com/Forum/424840/m ... 1142024932

http://www.network54.com/Forum/424840/m ... 1138021506

http://www.network54.com/Forum/424840/m ... 1127490846

It may take a few days to hear back from everyone, but Curt had lots of debris in his tank (see photos), Paul spoke of clogged lines leading to the fuel pump, Mark had ignition problems at the distributor, and the list goes on. After a few bent pushrods and carb rebuilds, as far as I know all the 427s on the forum are running like champs. Hope this helps get you started.

Regards,

Dave Mehl

Thanks Dave for the trailers and tip for the electrical. I didn't get a chance to try it out yet, but will this week. Talked to another guy who told me to look at the fuel lines. Perhaps they are collapsing he thought. I'd think the only way for this to occur is if something is plugging the line somewhere, hope not but will look at it as well.
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Bill
Bill

June 5th, 2006, 6:13 am #6

Hello Bill,

Welcome to the forum! Were going to find the problems with your boat, its just a matter of time.

Whatever the issue, it appears to be ancillary in nature and not "main mehcanical". Many old boat owners are so rattled at ancillary malfunctions, they end up getting hooked for tens of thousands of dollars worth of repowering, when all it really is may be the need for attention to detail and careful troubleshooting.

On one of my 427s, I got a zero compression in one cylinder, because the prev owner had set the valves so poorly. He didn't know what the heck he was doing, quite frankly. Once set properly, compression came up and the motor is still running great ten (10) years later. A 427 does not like to run if the valves are set too tight. Too loose, it will run, and make lots of valve noise, without developing full power. Set right, they're just beautiful.

Sooner or later you'll want to upgrade to the PERTRONIX ignition modules, there is a dedicated thread on this, and it's simple and cheap, and the benefits over running a 427 with ignition points are immense. Many 427 owners have done this.

Youve got a lot of issues with an engine that has not been run since 1999. Many times, well see more than one gremlin working at the same time. Dont assume its just one thing.

In your last comment, you said the engine overheated, missed, and died again. Question that needs to be outlined for me and the others who will want to comment, is the overheating a normal thing, does it overheat and then stall out, or did it just overheat this particular time? Also, what was the nature of the overheating, how hot did it get, did it make any special noises, etc.?

Also, have there been any mods to your motors? Are you running stock PCV valves, ballast resistors, and carbs? Did the boat once run well, and now is it acting up? Is this a raw water cooled motor, or do you have heat exchangers with antifreeze in the reservoir?

Are you running ballast resistors and the proper coils? If not, the coils may well be overheating and getting so hot theyre losing their ability to generate a spark and then fail. Changing to a new improper coil may just replicate the old problem. I think Dave had a good comment, when you lose power, do you actually have any spark? Need to know this (good comment Dave!).

Dave had another good comment, and thats the heat induced vacuum change. Its possible that the hot engine causes something to loosen up and admit more air below the carb somewhere in the intake system. The carb may be loose, the gasket may be admitting air under the carb.

My first guess, however, is obstruction within the fuel lines. It sounds like the engines run long enough to draw debris into an obstruction and then they choke out. Curt Hill had similar issues to yours and he found he had a lot of junk in his tanks. I have a buddy here in Nashville with a much newer boat, and he would run down the river several miles and every trip (when the engines got hot) he would stall out at the same general location. He thought it was the Bermuda Triangle of the Cumberland. He tried everything, but found eventually after changing out lots of parts, it was an obstruction that occurred at an anti-siphon valve in his fuel line. We old boat owners dont have anti siphon valves, but we do have shut off valves with 90-degree bends, etc. He finally found out he could run down the river for a while until particles finally built up enough to stall out his motor. Sounds just like yours.

Someone on the forum suggested hooking a temporary test fuel line to an outboard motor fuel tank, running off it to be sure your main tanks were not the issue. Doing so would guarantee you were getting a clean and unobstructed fuel supply. I suggested to Curt, that he hook up a suction to his fuel lines and pull out whatever it was down there, to test if it was a continual fuel supply. He changed out filters, etc., but finally found lots of debris was clogging his main flow to his fuel pumps. He pulled his pick-up tubes, and siphoned out lots of debris.

I would hope Tim Toth, Mark Weller, and Curt Hill, among others, Tom, Dave, Howard, Wes, would offer their comments too to help diagnose your issues. What we need are as many symptoms as possible.

For instance, when you tried to restart, did you look into the carb (with the motor off), and pump the throttle to see if you were getting jets of fuel squirted into the carb? If so, fuel starvation probably is not the issue. If you can see fuel squirting when you run the throttles all the way forward and back, and if youre getting a spark as Dave noted, then were ready to solve the problem, as theres not a whole lot of issues left.

I would wonder if when your engine stalls out, if it would restart and run if it was given a boost with starter fluid. This is not normally such a good idea, but starter fluid will make a motor start under just about any condition, vapor lock or not. I wouldnt recommend this, because I would satisfy my curiosity by checking for spark when the motor cuts off (as Dave recommended) and then Id look into the carb and see if it was overly wet (over choked) and also have someone pump throttles to see if you are able to see fuel being squirted into the carb. If you see fuel being squirted, I doubt if starvation is the issue.

Fuel pumps may be suspect. Malfunctioning choke may be suspect too. When you stall out, pull the flame arrestor off, look inside, and if you see the choke butterfly closed, the heat activated choke mechanism may be malfunctioning.

Here is a thread to Curt Hills sawdust in the tanks thread.
http://www.network54.com/Forum/424840/m ... 1146731677

Regards, all the best, gimme some help here fellas!

Paul
















Thanks for the reply's and questions. I'll start out by letting you know I just purchased the boat. It hadn't been run since 1999. Apparently the previous owner passed away, and his kids never got to take her out. From my interpretation of the records this boat had to have been in tip top shape when it was last run. The previous owner was a Retired Coast Guard Officer and Current Coast Guard Auxillary member. You wouldn't believe the documentation and logs that were kept. The safety stuff on the boat and prelaunch check sheets for every trip traveled suggest this girl was in perfect running condition all the time or it didn't leave port. Therefore, I can only assume the boat has been well taken care of and should be a simple little thing to fix.

Now to let you know a little about me and my diagnosis. I am not close to a mechanic, but I always find myself fixing engines out of necessity and the joy of figuring it out. Most of my fixes come from learning about the problem asking questions of mechanics, going to a parts store, ordering the part, then I search the engine until I see the look alike and replace it. I'm getting to the point where I know a little more than that, but in reality it's not much more than that.

So when I bought the boat I had a top notch marine mechanic get it running with no limit on funds to make sure it was perfect. The problem is it runs perfect in the garage, but once in the water it dies. The other engine runs perfect. He lives in Texas, I live in Idaho so taking it back isn't an option. This is what he did; he drained the fuel, changed the fuel filter, fresh water impellar, oil, fuel pump, 2 new batteries, rebuilt the carb, compression tested, timed, new cap and rotor, spark plug wires, and put in 50 gallons of super unleaded.

I got the boat delivered, and took my family out to dinner that night. The boat ran perfect for about 5 miles, we docked, ate dinner and headed home. I dropped my family off at our beach and when I went to put her away she missed a little (first indication something was wrong sludge in the fuel was my guess, took 10 miles to build up). Temp was about 175 (guage has marks 160 - 200) so can't be exact, but figure anything in the 160 - 200 range is good enough to keep it running. Oil pressure was about 80, fuel guage didn't read, but got her tied up and thought sludge in the fuel.

Took her out the next day and ran her hard (3,500 - 4,200 rpm) for about 15 minutes then it missed and died. I couldn't get it started again so had to limp home. All guages read good except for the fuel.

The next morning I drained the fuel tank and at first thought it had to be the fuel because of what appeared to be a lot of sludge, but the second 5 gallons came out clean and 40 gallons later I felt perhaps it wasn't the fuel. I put the fuel into my truck (including the first 5 gallons) and never had an issue. I replaced the fuel filter, spark plugs, alternator, replaced the fuel float and sender unit (extremely gunked), and repaired a wire to the regulator that had broken off. I also noticed a port coming out of the bottom of the carb that if I put my finger over it when it was running it picked up a little meaning it was sucking air straight into the carb so I closed this port off. Found out this was a vaccum port that should have been closed off.

I then thought for sure I had it dialed in asked my wife to jump aboard and we'd run over to the nearest marina and have some coffee (she's definately not too excited about another boat especially one that doesn't work). We got out 10 minutes I heard a miss so I backed her off to just idle speed and we cruised into the marina with no problem. Perhaps I've learned a little about when I'm with the wife getting there is a lot better than trying to hot rod it and end up paddling home.

I conned a buddy to head out with me for the next test run, and 15 minutes into it it missed, sputtered, back fired and died. All guages looked good. We pulled the hatch and water was everywhere. Thought I had a bad hose, but couldn't get the engine started again or feel anything unusual. We pumped the gas a couple of times, and sure enough we were getting fuel into the carb. Paul mentioned this might eliminate some things from the fuel side, is this right? I'm going to double check it, because when we were looking at this our intent was to start the engine not diagnose so looked at lots of things and didn't write them down or finalize that was the problem. Perhaps I pumped fuel at a later date when I was trying to diagnose and that is what I remember.

The next morning drained the gas again and then started her right up, and found the main engine water pump was seized. In my mind this had to be it. If you can understand why I thought this was it you can understand exactly how the boat performes before it dies. I thought when the thermostat would open at temperature it caused water to spray directly across the rotor, and what water escaped from there went straight into the carb causing missing, backfiring, dieing, and a too hot of engine that wouldn't let me restart it until it cooled off. Change the water pump and I can get my wife back out there is what I thought

I called my Texas mechanic and he recommended his most trusted source for a pump guy in Florida. He agreed without a doubt this was the problem. I called the guy in Florida and he convinced me if I was exclusive to fresh water to use an automotive pump as long as the rotation was correct. I would have to fabricate it so the closed thermostat water could cycle back into the fresh water pump. This was accomplished by pulling the old pump, and seeing what he was talking about. I had to tap a 1/2 pipe into the pump and conect the hose to this point. Exactly like the original. This allows the cold water from the fresh water pump to be diverted into a hose on a closed thermostat, back into the water pump and out the manifolds. Simplified somewhat, but that's the set up.

Not sure I liked putting the automotive pump on, but the guy in Florida builds marine pumps and assured me it was the same. I reinstalled it, took it out for a test drive, 15 minutes into it a repeat of how it died. However, the pump seemed to be working as it wasn't spraying water everywhere and the temp guage was 175.

Next talk was to a local marine mechanic who is swamped so didn't want to look at her, but before I could get the words out he said you have a bad coil. It takes that long for them to heat up and it would be his first place to go. I didn't tell him anything about all the previous stuff I had done so this was his first thought. He also said go to the autostore and get a coil it would be a cheap test. I also talked with a diesel mechanic about an automotive coil vs marine. He said it doesn't matter, but swore it had to be heat/water related. Change the thermostat. So I changed both.

Took her out again. 15 minutes into it she smelled hot and the temp guage read 200 - 210. I shut it down and limped back. At the dock I wanted to look to see if I had a thermostat housing leak, but couldn't get it started. Took the old thermostat and put it into hot water and sure enough it works okay. I'm planning on putting it back in because the replacement stat didn't look the same.

So for a rundown of the engine. I don't know for sure what's original and new. I know the fuel pump is a factory rebuilt marine pump, the coil and water pump are new, but automotive. The manifolds look stock and if anything perhaps the carb is an after thought. It's a Holley, and I've had other CC's and they have all been Carter's. It is hard piped to the fuel pump. The plug wires are some sort of racing set that I have a difficult time knowing if they are seated or not. I do not know about the the PCV valves and ballast resistors that Paul mentioned other than they are there. I've heard about the PERTRONIX system, but don't know the ins and outs of changing over or if it's worth it? I question timing. Some say it's not timed correctly, but my understanding is if it's not timed correctly then wouldn't the first 15 minutes also be missing? I read that 7 and 8 wires shouldn't be touching?

It is a fresh water cooling system and I like the thought of a bad choke. I was talking to the buddy I conned into going out with me and he wondered as an after thought being a Holley it's actually an electric choke. He wondered if it could be cross wired? At start up it's wide open, so could that mean when it heats up it actually closes? I haven't thought to look at it after it shuts down. We did when we tested to see if gas was getting into the carb, but can't remember if it was open or closed. We had our fingers, screwdrivers and pliers prodding all over the thing. Our intent was to get it going instead of understanding so didn't pay close enough attention. Because it starts right up when it's cold I'm contemplating disconnecting the wires anyway.

Hopefully this gives a pretty good description of what I know. Obviously a lot of words with a little detail, but because I don't know the correct lingo about diagnosing I'm describing the symptoms the best I can to hopefully spark some thoughts about what it could be. Any and all suggestions will be followed up on, until I get her perfect.

Thanks,
Bill


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Mark Weller
Mark Weller

June 5th, 2006, 5:23 pm #7

The electric choke may be out of whack or cross wired if it is open when the motor is cold turn on the key and watch the choke. If it is wired wrong it will close within about 2 min. My thoughts on this are many and we will need more info to diagnose but I would check the choke first. Although I don't think it would make the motor die just run poorly. I believe you have some other issue. You said the tanks have been drained a couple of times and you found junk in them both times. Take off the fuel filter and look at it and the gas that comes out of it see if there is any junk in it, if there is a lot of sediment you may have to flush those tanks a few times. Does this only happen to one motor if so do you have the ability to draw fuel from one tank only? Try drawing fuel from the tank where the motor keeps running and see what happens. If that fixes it you have an issue with the tank or the pickup tube or the fuel line from the tank to the crossover. That would be my first test after checking the filter as it is easy to do.
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Bill
Bill

June 6th, 2006, 3:56 am #8

Thanks for the reply's and questions. I'll start out by letting you know I just purchased the boat. It hadn't been run since 1999. Apparently the previous owner passed away, and his kids never got to take her out. From my interpretation of the records this boat had to have been in tip top shape when it was last run. The previous owner was a Retired Coast Guard Officer and Current Coast Guard Auxillary member. You wouldn't believe the documentation and logs that were kept. The safety stuff on the boat and prelaunch check sheets for every trip traveled suggest this girl was in perfect running condition all the time or it didn't leave port. Therefore, I can only assume the boat has been well taken care of and should be a simple little thing to fix.

Now to let you know a little about me and my diagnosis. I am not close to a mechanic, but I always find myself fixing engines out of necessity and the joy of figuring it out. Most of my fixes come from learning about the problem asking questions of mechanics, going to a parts store, ordering the part, then I search the engine until I see the look alike and replace it. I'm getting to the point where I know a little more than that, but in reality it's not much more than that.

So when I bought the boat I had a top notch marine mechanic get it running with no limit on funds to make sure it was perfect. The problem is it runs perfect in the garage, but once in the water it dies. The other engine runs perfect. He lives in Texas, I live in Idaho so taking it back isn't an option. This is what he did; he drained the fuel, changed the fuel filter, fresh water impellar, oil, fuel pump, 2 new batteries, rebuilt the carb, compression tested, timed, new cap and rotor, spark plug wires, and put in 50 gallons of super unleaded.

I got the boat delivered, and took my family out to dinner that night. The boat ran perfect for about 5 miles, we docked, ate dinner and headed home. I dropped my family off at our beach and when I went to put her away she missed a little (first indication something was wrong sludge in the fuel was my guess, took 10 miles to build up). Temp was about 175 (guage has marks 160 - 200) so can't be exact, but figure anything in the 160 - 200 range is good enough to keep it running. Oil pressure was about 80, fuel guage didn't read, but got her tied up and thought sludge in the fuel.

Took her out the next day and ran her hard (3,500 - 4,200 rpm) for about 15 minutes then it missed and died. I couldn't get it started again so had to limp home. All guages read good except for the fuel.

The next morning I drained the fuel tank and at first thought it had to be the fuel because of what appeared to be a lot of sludge, but the second 5 gallons came out clean and 40 gallons later I felt perhaps it wasn't the fuel. I put the fuel into my truck (including the first 5 gallons) and never had an issue. I replaced the fuel filter, spark plugs, alternator, replaced the fuel float and sender unit (extremely gunked), and repaired a wire to the regulator that had broken off. I also noticed a port coming out of the bottom of the carb that if I put my finger over it when it was running it picked up a little meaning it was sucking air straight into the carb so I closed this port off. Found out this was a vaccum port that should have been closed off.

I then thought for sure I had it dialed in asked my wife to jump aboard and we'd run over to the nearest marina and have some coffee (she's definately not too excited about another boat especially one that doesn't work). We got out 10 minutes I heard a miss so I backed her off to just idle speed and we cruised into the marina with no problem. Perhaps I've learned a little about when I'm with the wife getting there is a lot better than trying to hot rod it and end up paddling home.

I conned a buddy to head out with me for the next test run, and 15 minutes into it it missed, sputtered, back fired and died. All guages looked good. We pulled the hatch and water was everywhere. Thought I had a bad hose, but couldn't get the engine started again or feel anything unusual. We pumped the gas a couple of times, and sure enough we were getting fuel into the carb. Paul mentioned this might eliminate some things from the fuel side, is this right? I'm going to double check it, because when we were looking at this our intent was to start the engine not diagnose so looked at lots of things and didn't write them down or finalize that was the problem. Perhaps I pumped fuel at a later date when I was trying to diagnose and that is what I remember.

The next morning drained the gas again and then started her right up, and found the main engine water pump was seized. In my mind this had to be it. If you can understand why I thought this was it you can understand exactly how the boat performes before it dies. I thought when the thermostat would open at temperature it caused water to spray directly across the rotor, and what water escaped from there went straight into the carb causing missing, backfiring, dieing, and a too hot of engine that wouldn't let me restart it until it cooled off. Change the water pump and I can get my wife back out there is what I thought

I called my Texas mechanic and he recommended his most trusted source for a pump guy in Florida. He agreed without a doubt this was the problem. I called the guy in Florida and he convinced me if I was exclusive to fresh water to use an automotive pump as long as the rotation was correct. I would have to fabricate it so the closed thermostat water could cycle back into the fresh water pump. This was accomplished by pulling the old pump, and seeing what he was talking about. I had to tap a 1/2 pipe into the pump and conect the hose to this point. Exactly like the original. This allows the cold water from the fresh water pump to be diverted into a hose on a closed thermostat, back into the water pump and out the manifolds. Simplified somewhat, but that's the set up.

Not sure I liked putting the automotive pump on, but the guy in Florida builds marine pumps and assured me it was the same. I reinstalled it, took it out for a test drive, 15 minutes into it a repeat of how it died. However, the pump seemed to be working as it wasn't spraying water everywhere and the temp guage was 175.

Next talk was to a local marine mechanic who is swamped so didn't want to look at her, but before I could get the words out he said you have a bad coil. It takes that long for them to heat up and it would be his first place to go. I didn't tell him anything about all the previous stuff I had done so this was his first thought. He also said go to the autostore and get a coil it would be a cheap test. I also talked with a diesel mechanic about an automotive coil vs marine. He said it doesn't matter, but swore it had to be heat/water related. Change the thermostat. So I changed both.

Took her out again. 15 minutes into it she smelled hot and the temp guage read 200 - 210. I shut it down and limped back. At the dock I wanted to look to see if I had a thermostat housing leak, but couldn't get it started. Took the old thermostat and put it into hot water and sure enough it works okay. I'm planning on putting it back in because the replacement stat didn't look the same.

So for a rundown of the engine. I don't know for sure what's original and new. I know the fuel pump is a factory rebuilt marine pump, the coil and water pump are new, but automotive. The manifolds look stock and if anything perhaps the carb is an after thought. It's a Holley, and I've had other CC's and they have all been Carter's. It is hard piped to the fuel pump. The plug wires are some sort of racing set that I have a difficult time knowing if they are seated or not. I do not know about the the PCV valves and ballast resistors that Paul mentioned other than they are there. I've heard about the PERTRONIX system, but don't know the ins and outs of changing over or if it's worth it? I question timing. Some say it's not timed correctly, but my understanding is if it's not timed correctly then wouldn't the first 15 minutes also be missing? I read that 7 and 8 wires shouldn't be touching?

It is a fresh water cooling system and I like the thought of a bad choke. I was talking to the buddy I conned into going out with me and he wondered as an after thought being a Holley it's actually an electric choke. He wondered if it could be cross wired? At start up it's wide open, so could that mean when it heats up it actually closes? I haven't thought to look at it after it shuts down. We did when we tested to see if gas was getting into the carb, but can't remember if it was open or closed. We had our fingers, screwdrivers and pliers prodding all over the thing. Our intent was to get it going instead of understanding so didn't pay close enough attention. Because it starts right up when it's cold I'm contemplating disconnecting the wires anyway.

Hopefully this gives a pretty good description of what I know. Obviously a lot of words with a little detail, but because I don't know the correct lingo about diagnosing I'm describing the symptoms the best I can to hopefully spark some thoughts about what it could be. Any and all suggestions will be followed up on, until I get her perfect.

Thanks,
Bill

I went out again tonight after reinstalling the old thermostat, and think it might be water related. Right from the dock it started overheating to 200 degrees at 800 rpm. The engine died again and the engine was definately hot so I took out the new impellar on the fresh water pump thinking for sure it was the problem, but it looked okay. My expectations were there would be no rubber left. I know looks don't tell the truth so will replace it, but when I opened the pump I could barely touch it it was so hot.

Is this normal for the freshwater pump to be hot? In addition, it was bone dry. Didn't know if this was normal either. Is there an easy way to look for circulation? I saw the water flow diagram and suggestion of a clogged manifold that was referenced in the trailers, but didn't know where to start.

I believe the boat was ran in saltwater as it was moored on a freshwater lake that dumped into the Gulf of Mexico. The engine looks great so if it did hit salt water the previous owner must have flushed it with freshwater.

Also after it died I checked fuel, and I had fuel at the carb when stroked. I also had spark at the plug. Both ideas gave me confidence so thank you.

Any suggestions would be appreciated.

It seems each time I take it out it's getting worse.

Thanks,
Bill

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Paul
Paul

June 6th, 2006, 5:20 am #9

Hello Bill,

Running an impeller dry won't do it any good, they'll get real hot and they'll wear too. A proper impeller and pump will prime the pump with a slight amount of suction. It's not too much of a lift because the motor is so low in the boat, but there is a slight vacuum to do this. A malfunctioning pump won't create the suction, I suppose you could put some water in through the top to help with initial lubrication of the pump to create that initial prime, but something is keeping the pump from priming itself and this needs to be fixed because it will just act up again later. An improper impeller won't create any suction either, side clearances are VERY important.. They are not supposed to be run dry, and they are not supposed to be hot.

If the impeller is working, and the seacock is open and the hull strainer and strainer container are free flowing, you WILL get water into the motor.

I'm wondering if the seacock is fully open to allow flow to the pump? Has there been ANY water circulating? Surely there has been some water, or the rubber exhaust pipes would be totally cooked. I suppose you could use a garden hose to check flow, but don’t put city water pressure into the motor, because it’s not designed for that. You could flow water gently to the circulating pump, and you could also blow water down through the intake strainer, to double check flow there by backflushing.

I didn't see an answer from you about the type of cooling on this motor, so I am assuming you have the standard (raw water) cooling and NOT the heat exchanger system. Here is the standard diagram.

Note the water all goes through the reverse gear oil cooler first, where it is split into various routes back into the motor. This entire flow could be checked with a garden hose if you took the time to do so, by hooking the hose to the motor side of the reverse gear cooler. However, since your sea water pump was dry, it seems it's the problem.

It would be easy to disconnect the hose leading to the reverse gear oil cooler, to establish water flow from the sea water pump. It would also be easy to unhook the two long copper pipes that run parallel to the valve covers on their way to the riser, to check for flow there too. A couple lengths of clear tubing might be interesting too, just for testing to observe water flow (that water will be hot, and clear tubing won't last much longer than a test run or two). Each side should have the same degree of flow out of the motor.

Having a motor stall out because it got too hot isn’t a good thing. If you have good oil in the motor, chances are you have not done any serious damage as long at the motor didn’t seize up.

The carb won’t function properly if things are too hot, so this may be part or all of the issue, but one thing is certain, and that’s the fact that you MUST find out why you are not getting water though the motor. Once you get water flowing, and verified by short runs, disconnected water hoses diverted safely to the bilge, etc., then you can go after any remaining running problems. Sounds to me you have the wrong impeller??????

Good luck, keep us posted!

Regards, Paul
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Paul
Paul

June 6th, 2006, 5:24 am #10

Wonder if the sea water pump isn't the proper rotation, getting hot, and never going to pump water? Your earlier post indicated the motor would run fine at the dock, but upon running at speed it would overheat. Obviously water was circulating at one point.

Just start verifying flow starting at the pump, or some close logical other location, and work your way back.

Good luck,

Paul
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