Everyone better check their CC pressure regulators

Everyone better check their CC pressure regulators

Paul
Paul

November 24th, 2006, 11:34 pm #1

As a graphic aid, see the following thread where there are diagrams of the 427 systems. My comments here are for all systems, not just the 427 system.
http://www.network54.com/Forum/424840/m ... 1123102009"

-----------------------------------------------------------------
In addition, anyone wanting information about their Sherwood sea water pumps, check out the following two links.

Sherwood sea water pump as used on the 283F, 327F, and 427
http://www.network54.com/Forum/424840/m ... 156595176/

Old style 4-port Sherwood as furnished on the early flywheel forward 283.
http://www.network54.com/Forum/424840/m ... 156386823/
------------------------------------------------------------------


ABOVE: The CC Pressure Relief Valve, probably not touched for 20, 30, or 40 years and needing minimum attention, but subject to being held open if debris gets into the system. See threads below for lots of additional photos.


Today as I was working on my latest restoration project, I discovered something I want to pass on to everyone. I hooked up a water source to my 327F, fired up the motor, and the exhaust manifolds were overheating. I shut things off, ran the hose some more, took off some of the fittings, and I discovered water was not reaching all parts of the motor. Why?

Well here's why on the 327F, and this may well apply to many of our CC motors. The 327 is tilted with the forward part of the motor higher than the prop shaft side, like most of our motors are. Mercrewser's is tilted the opposite direction, but he's running a V-drive, but the same issue will apply.

Water runs uphill only when it's pressurized. For some reason I couldn't make water run uphill to the front of the motor, but when running a lot of water through the motor, and seeing it come out the tailpipes, I was puzzled (for a minute or two).

Since I knew the water was making its way to the tailpipes, I decided to take a look at those pressure regulators at the back of the motor, in this case they are attached to the risers. Sure enough, BOTH were stuck open, due to debris. One looked like it had a little twig holding it open, and the other had a bit of debris I couldn't identify. I took both apart, ran a screwdriver around the parts that touch, and cleaned em out. This time when I put things back, those valves kept water from immediately draining out of the back of the motor, and allowed the water under pressure from the hose and water impeller, to reach the front top side of the motor.

With those pressure regulator valves being held open, the water took the path of least resistance, and it drained immediately out the back of the motor.

If anyone has LOW SPEED OVERHEATING, a pair of stuck open pressure regulator valves could well be all of or part of the problem.

When you're under idle conditions, those valves cause almost ALL of the water to go through the motor. When engine speed increases and the pressure builds up inside the motor, they open up and allow water to be wasted right into the riser. If these guys are stuck open, you may be able to run well at speed, but when you slow down your motor may be starved of water, and looking at the tailpipes could be very misleading because you'll still have water coming out (but it will be short circuited, as your motor is cooking).

Regards, Paul
Last edited by FEfinaticP on December 12th, 2006, 3:50 pm, edited 1 time in total.
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Joined: March 14th, 2006, 3:44 pm

November 25th, 2006, 3:51 pm #2

On Aug 5th & 8th I posted two threads regarding rising temps. in one engine at idle speeds.I too found a wee bit of crud in one of the pressure relief valves,cleaned it out and end of problem.
So if anyone is noticing a higher than normal temp. at idle or lower RPM's and you suspect raw water intake pump impeller or worn pump cam,save some time and a permanent flame arrestor nut imprint on your chest and check out those relief valves first, cause' they're a lot easier to get to!
Only six months til 07 launch!
Regards, Steve
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Joined: January 4th, 2006, 10:39 pm

November 26th, 2006, 2:43 pm #3

Hello Steve,

I saw your info in August, and upon reading it, I took action and checked my relief valves. Mine were functioning well at the time, but they looked like they were about to crap up, so I cleaned them up. Thanks for the post, you may be responsible for my cool running late this summer.

Howard
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Joined: March 14th, 2006, 3:44 pm

November 27th, 2006, 3:12 am #4

Thanks Howard.
The PO had told me that the port engine always ran a little warmer than the starboard at idle speeds and his corrective action was to just bump up the throttle a bit on the port side and that would bring the temp. down to normal.
That advice just didn't sit right with me and I decided to find the problem.
I posted the question to the forum, got some sage advice and solved the problem.
Ah, the beauty of the Web!!
Regards, Steve
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Paul
Paul

November 29th, 2006, 12:43 pm #5

On Aug 5th & 8th I posted two threads regarding rising temps. in one engine at idle speeds.I too found a wee bit of crud in one of the pressure relief valves,cleaned it out and end of problem.
So if anyone is noticing a higher than normal temp. at idle or lower RPM's and you suspect raw water intake pump impeller or worn pump cam,save some time and a permanent flame arrestor nut imprint on your chest and check out those relief valves first, cause' they're a lot easier to get to!
Only six months til 07 launch!
Regards, Steve
I like to cross reference threads like this, because it really helps people troubleshoot their own boats.

Here are the threads posted by Steve, which reinforce the need to check those pressure valves!

http://www.network54.com/Forum/424840/m ... 154826022/

http://www.network54.com/Forum/424840/m ... 1155048215
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Dave Mehl
Dave Mehl

November 30th, 2006, 10:57 pm #6

As a graphic aid, see the following thread where there are diagrams of the 427 systems. My comments here are for all systems, not just the 427 system.
http://www.network54.com/Forum/424840/m ... 1123102009"

-----------------------------------------------------------------
In addition, anyone wanting information about their Sherwood sea water pumps, check out the following two links.

Sherwood sea water pump as used on the 283F, 327F, and 427
http://www.network54.com/Forum/424840/m ... 156595176/

Old style 4-port Sherwood as furnished on the early flywheel forward 283.
http://www.network54.com/Forum/424840/m ... 156386823/
------------------------------------------------------------------


ABOVE: The CC Pressure Relief Valve, probably not touched for 20, 30, or 40 years and needing minimum attention, but subject to being held open if debris gets into the system. See threads below for lots of additional photos.


Today as I was working on my latest restoration project, I discovered something I want to pass on to everyone. I hooked up a water source to my 327F, fired up the motor, and the exhaust manifolds were overheating. I shut things off, ran the hose some more, took off some of the fittings, and I discovered water was not reaching all parts of the motor. Why?

Well here's why on the 327F, and this may well apply to many of our CC motors. The 327 is tilted with the forward part of the motor higher than the prop shaft side, like most of our motors are. Mercrewser's is tilted the opposite direction, but he's running a V-drive, but the same issue will apply.

Water runs uphill only when it's pressurized. For some reason I couldn't make water run uphill to the front of the motor, but when running a lot of water through the motor, and seeing it come out the tailpipes, I was puzzled (for a minute or two).

Since I knew the water was making its way to the tailpipes, I decided to take a look at those pressure regulators at the back of the motor, in this case they are attached to the risers. Sure enough, BOTH were stuck open, due to debris. One looked like it had a little twig holding it open, and the other had a bit of debris I couldn't identify. I took both apart, ran a screwdriver around the parts that touch, and cleaned em out. This time when I put things back, those valves kept water from immediately draining out of the back of the motor, and allowed the water under pressure from the hose and water impeller, to reach the front top side of the motor.

With those pressure regulator valves being held open, the water took the path of least resistance, and it drained immediately out the back of the motor.

If anyone has LOW SPEED OVERHEATING, a pair of stuck open pressure regulator valves could well be all of or part of the problem.

When you're under idle conditions, those valves cause almost ALL of the water to go through the motor. When engine speed increases and the pressure builds up inside the motor, they open up and allow water to be wasted right into the riser. If these guys are stuck open, you may be able to run well at speed, but when you slow down your motor may be starved of water, and looking at the tailpipes could be very misleading because you'll still have water coming out (but it will be short circuited, as your motor is cooking).

Regards, Paul
Great stuff you can learn on a forum like this. Sure takes the mystery out of some of these issues. The pressure valve situation is one I plan to look into at the onset of next season. Thanks for the tips, it's right at the top of the chart.

Dave
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Paul
Paul

December 10th, 2006, 10:26 pm #7

As a graphic aid, see the following thread where there are diagrams of the 427 systems. My comments here are for all systems, not just the 427 system.
http://www.network54.com/Forum/424840/m ... 1123102009"

-----------------------------------------------------------------
In addition, anyone wanting information about their Sherwood sea water pumps, check out the following two links.

Sherwood sea water pump as used on the 283F, 327F, and 427
http://www.network54.com/Forum/424840/m ... 156595176/

Old style 4-port Sherwood as furnished on the early flywheel forward 283.
http://www.network54.com/Forum/424840/m ... 156386823/
------------------------------------------------------------------


ABOVE: The CC Pressure Relief Valve, probably not touched for 20, 30, or 40 years and needing minimum attention, but subject to being held open if debris gets into the system. See threads below for lots of additional photos.


Today as I was working on my latest restoration project, I discovered something I want to pass on to everyone. I hooked up a water source to my 327F, fired up the motor, and the exhaust manifolds were overheating. I shut things off, ran the hose some more, took off some of the fittings, and I discovered water was not reaching all parts of the motor. Why?

Well here's why on the 327F, and this may well apply to many of our CC motors. The 327 is tilted with the forward part of the motor higher than the prop shaft side, like most of our motors are. Mercrewser's is tilted the opposite direction, but he's running a V-drive, but the same issue will apply.

Water runs uphill only when it's pressurized. For some reason I couldn't make water run uphill to the front of the motor, but when running a lot of water through the motor, and seeing it come out the tailpipes, I was puzzled (for a minute or two).

Since I knew the water was making its way to the tailpipes, I decided to take a look at those pressure regulators at the back of the motor, in this case they are attached to the risers. Sure enough, BOTH were stuck open, due to debris. One looked like it had a little twig holding it open, and the other had a bit of debris I couldn't identify. I took both apart, ran a screwdriver around the parts that touch, and cleaned em out. This time when I put things back, those valves kept water from immediately draining out of the back of the motor, and allowed the water under pressure from the hose and water impeller, to reach the front top side of the motor.

With those pressure regulator valves being held open, the water took the path of least resistance, and it drained immediately out the back of the motor.

If anyone has LOW SPEED OVERHEATING, a pair of stuck open pressure regulator valves could well be all of or part of the problem.

When you're under idle conditions, those valves cause almost ALL of the water to go through the motor. When engine speed increases and the pressure builds up inside the motor, they open up and allow water to be wasted right into the riser. If these guys are stuck open, you may be able to run well at speed, but when you slow down your motor may be starved of water, and looking at the tailpipes could be very misleading because you'll still have water coming out (but it will be short circuited, as your motor is cooking).

Regards, Paul
I took some photos the other day and thought I'd upload em today. In case any of you guys have not seen the inside of your PRV, here's what they look like.


There is some variation, but they're essentially all like this. Pretty simple disassembly, just undo the fasteners, tap it a bit to break it loose.



Here's what it looks like inside. It's a spring loaded valve that opens with pressure and allows excess pressure to bleed off into the exhaust system. The CC system creates an abundance of water and pressure at speed, so this is a safety valve. At low speed, if this thing is held open by debris, they the intended level of water won't be getting to your motor block, thus the low speed overheating with a bad PRV.


Here's what the backside (spring side, or the "pressure side") looks like. Pretty simple, essentially lasts forever.


(see next post for followup, to not overload this one with large photos)

Regards, Paul




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Paul
Paul

December 10th, 2006, 10:32 pm #8

Here's what the front side looks like.


Here's how the valve works, when pressure builds up on the water pump circuit, the valve is forced open and water flows around the opening. A very simple device, and a pretty easy one to work on.


After a light buffing on the brush wheel, and a light scrub with a gun cleaning brush, I soaked the valve in CLR to remove any corrosion. If you use a stainless steel brush, for instance, you'll leave lots of small scratch marks in the soft "yellow metal" and this will just attract debris.


The idea wasn't to make this part a show piece, but just to clean it up so it was free of junk and operated cleanly. This is a quick operation, and well worth the time to do it. The main issue now, is to get a gasket back in place so the valve closure piece won't leak.

Regards, Paul
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Dave Mehl
Dave Mehl

December 11th, 2006, 4:20 pm #9

Paul, it looks like the entire valve is brass, which is a good thing. I am wondering, since you have been working on these, did you see anything with rust on it? Hopefully they are all brass.

Thanks,
Dave
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Paul
Paul

December 11th, 2006, 4:45 pm #10

Virtually everything including the spring was made of brass. These probably last the lifetime of the boat. Real QUALITY piece of work!

Paul
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