Holley choke and tuning trouble
The 2bbl Holley list 80179 on my '83 F-150 is about to drive me nuts. I've been battling an issue with the idle speed and an off idle stumble for a while now. I got the stumble fixed this weekend (along with a minor fuel leak) after replacing the accel pump diaphram that was rock hard and cracked. I have made no headway against the excessively high idle speed though. When the engine is at ambient temp's, the electric choke does its thing and the engine start easily enough, but then the rpms climb to anywhere from 1100-1500 rpms. Once the engine is warmed up, I cannot get the choke to release at all. I can manually release the choke by hand under the hood, but as soon as I touch the gas peddle the rpms immediately jump back up high. It makes driving this thing a real pain in the arse because it pulls against the brakes hard when sitting at a stop while in gear, plus the high rpms really reduce the brakes effectiveness in stop and go traffic. Even with the choke manually disengaged, it still idles at 1000-1100 rpms (800-900 rpms in gear, as long as you don't touch the gas peddle), and will idle no lower in park. The only idle speed adjustment on this thing is from a solenoid controlled, vacuum operated "throttle kicker" that I have completely removed (and plugged off its vacuum line), but there was no change in idle speed at all. I have rotated the choke coil housing as far as it will go but this also had no effect. I even removed the rod that connects to the choke butterfly in the airhorn but that didn't help either. It does appear that someone has been in the carb before...is it possible that they wound the spring in the choke mechanism too tightly? I am flat out of idea's here.
The tuning issue I am having is that the carbs idle mix screws are almost totally unresponsive. At 1000 rpms the engine pulls 15.5" vacuum...considerably less than what I would expect from a bone stock engine. And with the high idle speed, if I don't kill the engine while its in gear, it diesels BADLY. It sometimes even does it just a bit while in gear.
I haven't removed the carb from the manifold yet, but it certainly seems to me like the throttle is open too far, but I can't really tell from looking down the thru the top of the carb as it has these large, weird boosters on it with cross patterns across the tops of them.
BTW, what does a "542" jet equal? I thought all holley jet sizes where 2 digits?
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