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I've got a mildly-built 181 Mercruiser engine in my Model A. I've got two Carter/Webber carbs on a homemade intake.
It has been running great, idling smooth and accelerating like a bat outta helloooo....but all of a sudden, it developed a dead miss on cylinder numbers one and two. When I rev it up, it clears up but has a lot less power...which indicates to me it's running on just one carb.
I took the carb apart, cleaned it (no sign of debris) and replaced it. Checked for vacuum leaks, timing, even did a compression test (It has 155 lbs on each cylinder).
The engine still runs at lower RPM like a John Deere! Rev it up and it clears up....just like before. Nothing I've done has helped. Folks, I sure could use some help!
Lord, let me live long enough to do all the projects I have planned!
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Dear Dennis;
Start with a compression test.
Good luck, John M., #3370....
John M., I.I. #3370
"There are no shortcuts to any place worth going". -Anon
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John, he did a compression test, 155 each cylinder
Terry/Novaconv I.I. #3948
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Maybe you could try a unisink to balance the carbs. mike...
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Dennis Do you have a pic of the intake??& carb set up??
Also have you tried to swap the carbs To see if the miss moves to 3-4 to prove it maybe a carb issue?? Because It almost seems to me as a Elec. Issue NOT carb.
#3220 }[oooooo]
Larry/Twisted6 [oooooo] Adding CFM adds boost God doesn't like ugly.
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Dist cap, rotor, coil....possibly
1951 Ply Concord truck 1954 Nash Rambler 2 dr 1955 Nash Rambler Farina
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D;
Try to move the manifold carb assembly by hand when idling. See if idle speed changes.
JM.....
John M., I.I. #3370
"There are no shortcuts to any place worth going". -Anon
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I'm thinking John H. could be on to something.A leak on the intake can drive you wonkers trying to diagnose.Good luck.
"Keep it simple ------!"
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Well, I appreciate all of your suggestions, but I've done everything you suggested, except switch carbs. I'll do that tonight. This is beginning to drive me nuts; it just began all of a sudden! Maybe those 1983 Carter/Webbers Carburetors is too advanced for my 1940 single-barrel brain!
Lord, let me live long enough to do all the projects I have planned!
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Dennis. I think Tom Langdon could shed some light on this. He sells these and he certainly has the background! I've never had him say he's to busy to answer my questions.
1951 Ply Concord truck 1954 Nash Rambler 2 dr 1955 Nash Rambler Farina
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I was thinking exhaust might be leaking into the intake of 1&2. Homemade manifolds require a little "shake down" sometimes.
JM...
John M., I.I. #3370
"There are no shortcuts to any place worth going". -Anon
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I talked to Tom last night and he gave me some suggestions. I'm gonna try to spend the day tomorrow on the Model a and see if I can get it sorted out.
John, the engine was running good for almost a year, with no problems...this just sprang up all of a sudden. I've been driving it up and down the country roads around here with only the chassis, doing buurn-outs lie a kid (I'm 64 going on 14, my wife says) and then with the unfinished body mounted. (I'm sure a Pennsylvania trooper would have loved to catch me doing that!) Now it's almost ready for the road and this problem comes up!
Lord, let me live long enough to do all the projects I have planned!
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51 Ford F1
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Hey, I found the reason for the dead miss on cylinders number 1 and 2. The intake gasket, beneath the 1/2 intake port was leaking.
When I was trying to find the miss before, I sprayed WD-40 around gaskets at the carbs and between the manifold and head...with no change in missing. However, today I sprayed WD-40 UNDER the intake manifold, at the gasket, and the engine sped up!
Instead of using the metal-reinforced gaskets, like the originals, I used heavy duty gasket material...not good! It couldn't hold up. One more lesson learned!
Lord, let me live long enough to do all the projects I have planned!
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