I have a Holley 4160 390CFM 4bbl carb with vacuum secondaries on my 1959 Ford 292 Y Block standard shift vehicle. I started the engine and the engine had it's usual curb idle of about 750 RPM. There is an inline filter at the carb and a filter mounted at the gas tank before the electric fuel pump. Then, I shut it off and added some antifreeze. Restarted the engine and now the engine won't idle unless the curb idle is around 1100 RPM. I did not do anything else to the engine and never touched the carb. I don't think the anti-freeze has any bearing on the problem. I don't want to start taking the carb apart without first having some idea about what might be causing the problem. The carb is about 10 years old and has always run great both at curb idle and on the road. Any suggestions and info. are very much appreciated. Thanks.
Did it back fire through the air cleaner? Might have blown the power valve. Could have developed a leak in the float if it has brass floats. Check your float level. Bones
You might want to check to see if the secondaries might have somehow gotten stuck open a touch, although it seems unlikely considering you didn't touch the carb.
I think what he meant, is that if he lets off the throttle, it dies. He has to keep it above 1100 rpm to keep it running, because it dies at idle.
Maybe coincidentally a filter got a little plugged up just then, or a piece of dirt managed to get stuck in a passage in the idle circuit, or idle mixture screws could have vibrated out a little, just enough to mess with things.
That don't mean a new Pope either. Head gasket? Is coolant disappearing why you're adding anti-freeze?
Did the idle go up by itself? Or would it just not stay running at idle and you adjusted it higher? I've inadvertently pulled off a vacuum hose while working under the hood. Starts idling higher. When you rev it, the rpms hover before settling down. If not, I'd agree about debris in the carb being a likely suspect. If that's the case and it's starving for fuel, it might have a tendency to "pop" or hesitate a little under acceleration and cruise speed. It might pop pretty good on deceleration too.
Try the shade tree tune up! Get it running and then pull the throttle wide open AND quickly clamp your hand over the top of the carb. When it almost dies...remove your hand and let it start to speed up again and clamp your hand on top of it again. It pulls a tremendous amount of vacuum thru the carb and "sometimes" that will clear out the trash. Won't hurt anything unless you go to sleep and let the durn thing over rev...float the valves...throw a rod through the side of the engine...make you bang your head on the bottom of the hood..something-like-that! 6sally6
I've had enough power valve problems with Holley 4 barrels to make that my first thought. It could be crap caught in the idle circuit too. If you don't like 6sally6's method you can pull the idle mixture screws out and blow the idle circuit clear with compressed air. You're gonna have to readjust the mixture when you're done though, maybe a good idea anyway. Both methods work with varying success.
The carb is 10 years old and it's acting up and your bitching , clean it ,put a kit in it , add a power valve protector, and be glad you got 10 years out of it ,. Sheeeeesh !
I am not complaining and I am glad it lasted 10 years. No need to get nasty! Working on a car in the bitter cold is not fun as you get older. I do thank all who responded for their help.
Nope. I knew someone would think that. It's my brother's car in upstate NY. Since he is not good at posting things on the computer I was asking for him. Then I email him the HAMB link and he can open it. Hope that not against the HAMBurger Code of Justice. By the way, thanks again for the replies. I am sure he will benefit. Merry Christmas to all.
Lighten up, dude. My carb has been on for over 20 years without a problem. Haven't touched it. Shouldn't have to.
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