Rebuilt 4100 idle screws and adjustments.

Rebuilt 4100 idle screws and adjustments.

Joined: February 12th, 2009, 1:41 am

April 25th, 2010, 11:11 pm #1


I have tossed the Holley and placed my 4100 on my 289. Idles fine when the screws are turned in all the way. After taking the top off , I wasn't sure the fuel level was on and set it 1 in below the lid on both floats. The idle screws seemed to be adjusting out a bit. They are now on the drivers side 1-1/4 out and the passenger side only 3/4 out. Can't seem to get the standard 1-1/2 starting point. Have yet to check the power valve or secondary butterfly setting but the butterfly's didn't look opened too far . Could the passages be plugged. The floats were also the old brass ones and I used a set of newer black foam ones that were in another carburetor. My timing is set at 14 degrees and ran fine with the other carb. Should I try to clean the idle passages. I don't want to harm the carburetor. This is a 108cfm carb.


Thanks
Greg
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Joined: February 12th, 2009, 1:41 am

April 26th, 2010, 12:14 am #2


I took the carburetor off and took a look at the power valve cover. There was no apparent gas coming out of the cover when it was running, but after removal the gasket and inside was wet. Is this a case that the power valve is faulty or not tightened enough. The p[ower valve was not the style that I have from a Ford CT-191 rebuild kit. The number is 8.5 and looks like a Holley PV. Now that it is off is there a wire or technique to go through the idle passages.


Thanks

Greg
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Lee
Lee

April 26th, 2010, 2:18 am #3

will show a little wetness due to the vacuum passage which supplies vacuum from the venturi bore. Fuel can condense in the power valve chamber when the engine shuts down. If the power valve itself is dry, it probably isn't leaking. With fuel in the bowl, just feel for fuel around the P/V. If it's dry, you're good. Wet, then there is either a problem with the P/V gasket...or the valve itself. If the P/V is bad, the engine would probably run with the needles closed all the way since the engine will suck in fuel through the P/V vacuum passage, bypassing the idle system. Also, a bad seal between the P/V cover and carb body will prevent the P/V from closing at vacuum above 8.5" and cause a tough to find vacuum leak. So I don't think your needles are anything to worry about if you can now kill the engine by closing them all the way. You have a P/V on the higher end of the scale, you could try a 6.5".
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Joined: February 12th, 2009, 1:41 am

April 26th, 2010, 3:17 am #4


I had one from the Ford rebuild kit and will give it a try. I think the wetness is as you have stated. The cover and gasket will be checked before install. Hope the guys that rebuilt this put it in good cleaner to get the dirt and varnish out of the passages. Have you heard of Autoline in Canada. This is the 3rd carb with the idle screw issue.

Thanks

Greg
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Joined: January 11th, 2010, 4:03 pm

April 26th, 2010, 10:56 am #5

Autoline rebuilt my carb. I got it from Autozone. I actually called Autoline and they searched their inventory for the carb I wanted, It had the wrong booster though. The primary booster was so wrong that the idle needles had no effect. I got the proper boosters from a fellow board member.

The carb was very clean though and it now runs perfect.

Duke
66 Sunbeam Tiger
Fort Leavenworth, KS
Last edited by 66SunbeamTiger on April 26th, 2010, 10:57 am, edited 1 time in total.
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Joined: February 12th, 2009, 1:41 am

April 26th, 2010, 12:45 pm #6


As you have mentioned Duke, the product looks fantastic when you get them. I am going to check my casting number and the boosters. I will post the information and maybe I have mixed boosters as well. The choke has been plugged off right now with some rubber tips for vacuum ports on the hook up for the hot air and the cold air port on the air horn. Hope the blocking of the air flow isn't causing this issue.


Greg
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Lee
Lee

April 26th, 2010, 5:59 pm #7

is hooked up, the engine will see an A/F mixture which is slightly leaner 'cos there is no fuel being sucked into the engine from the choke plumbing...only clean air. Try simulating the factory design by running and tuning your car after uncapping the choke's vacuum port.
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Joined: February 12th, 2009, 1:41 am

April 26th, 2010, 11:07 pm #8


This carburetor is a bit of new territory for me. I will try the carburetor with the engine warmed up and choke connections open. Thanks Lee.


Greg
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Joined: February 12th, 2009, 1:41 am

April 27th, 2010, 3:46 am #9


Just checking to make sure the boosters are correct. The carburetor is a C5ZF E with the primary CS and the secondary A. As was stated by Duke, the wrong booster caused an issue for him.


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Greg
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Joined: January 11th, 2010, 4:03 pm

April 27th, 2010, 1:47 pm #10

I am 90% sure those are correct. I'll check my book at lunch to make sure.

Duke
66 Sunbeam Tiger
Fort Leavenworth, KS
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