Stripgear Posted September 16, 2011 Share Posted September 16, 2011 My '62 Skylark (215 V-8) started running rough when warm. If I manually close the choke, it runs great. So I take the carb apart looking for either a vacuum leak or fuel restriction. Well, I found a "vacuum leak". If you look at the pictures, you will see an intentional path to allow unmetered and unfiltered air into the carb above the throttle plates. I have a spare carb and unopened carb kit, and they are all the same. I've never seen this before. I guess I'll never hose down the engine...Scott Link to comment Share on other sites More sharing options...
carbking Posted September 16, 2011 Share Posted September 16, 2011 Click on the link to "Throttle body gaskets"THE CARBURETOR SHOP / TroubleshootingJon. Link to comment Share on other sites More sharing options...
NTX5467 Posted September 16, 2011 Share Posted September 16, 2011 Interesting situation! If the design had been to have the "vent" under the throttle plates, then it would have been a vacuum tap for power brakes or similar . . . but as it's not threaded AND where it is, the hot idle "fix" make sense with respect to a "hot soak" situation.Thanks for that link, Jon!NTX5467 Link to comment Share on other sites More sharing options...
trimacar Posted September 17, 2011 Share Posted September 17, 2011 Man, I'm glad my carburetor is carbing, my generator is genning, and my pistons are......working too.... Link to comment Share on other sites More sharing options...
old-tank Posted September 17, 2011 Share Posted September 17, 2011 ScottI know we have been through this before, but your problems may be related to the available fuel (ethanol). Also my advice (that I don't always follow) is to be sure that your ignition system has no issues. When I put the 264 nailhead in my 51 F-1 I used the spark plugs that were in it --- Bosch platinum, right number and they looked new. Anyhow when hot it would idle roughly and was very hard to start. Finally after tearing the carb apart 3 times I checked one of the plugs on a lawn mower where it had a very thin barely perceptible spark...I then tried a used AC44 and the spark was splat,splat,splat....new plugs and it runs perfectly.Also I noticed that your carb is probably a Rochester 4gc. One of our local chapter members had an engine fire in his 62 after one of the bowl plugs popped out (another effect of ethanol on the original cement). Also the current gas if left to dry in the carb leaves a white powdery residue. The 4gc on one of my 55's did not like that residue...I could clean it and it would run perfectly until the next time it dried out. That 4gc is in a box...the only carb that ever defeated me!Willie Link to comment Share on other sites More sharing options...
Stripgear Posted September 17, 2011 Author Share Posted September 17, 2011 Willie,Thanks for the input. I will will definitely do some more checking after the weather cools off some. However, this really seems just to some "junk" in the carb. I took it apart and blew it out, and now it runs fine. Scott Link to comment Share on other sites More sharing options...
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