Hy guys, I just received a call from a friend who is trying to dyno a freshly rebuilt 261, he sent his carburetor down to California to be rebuilt and has used the rebuilder before with good results. The carburetor is an automatic choke type Rochester. The engine is stock except for an H.E.I. distributor. He said the engine is leaning out below 1200 rpm and wont idle below that rpm. He has checked for vacuum leaks and corrected those he found. His call was to check and see if I had a carburetor for a 261 and I told him I would have to look at all my carburetors to see if I could locate one that was definitely for a 261. He has verified the timing and the engine runs well except when trying to idle it down, it sure sounds carburetor related to me, anybody have any suggestions, thanks in advance.
Have him check on the idle mixture passage that aligns with the mixture adjusting screw. It sounds like the carb isn't flowing any mixture through the low speed system. Also try this- - - -back the idle mixture screw out 2-3 turns, rev the engine up to around 1500-2000 RPM and slap your palm or a big rag over the carb inlet. Do this several times. Sometimes, the heavy choking action will draw liquid gas through all the passages and flush out debris that's clogging them up. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Just as a matter of asking, are you 100% sure the choke is functioning correctly, that it is actually pulling off and the choke rod is unloading the idle speed screw off the fast idle cam?
Hy guys, thank you very much for the suggestions. Hotrod Lincoln, I have used that trick a few times in my career, sometimes it works sometimes it doesn't, but no harm in trying it. Dragsix, also a good suggestion on something to check, I'll contact my friend with both suggestions. I'll see if I can go and look at things myself just in case I can see something that others haven't noticed. Thanks again
Hy Guys, an update, I had "E' mailed my friend with your suggestions, but I didn't get a reply from him, so I went to see him, turns out he changed his "E" mail address. Now to the engine, he found another carburetor for the 261 installed it and the engine performed as it should right down to idling. Thanks again for your suggestions!
