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I have a problem with trying to get my carb adjusted correctly.It will start immediately cold and fast idle but the problem I have is when the choke first comes off and the engine is not completely up to temp it will idle really slow and possibly die. And then when its fully warmed up it will idle faster. I have also noticed I have to have the idle mixture screws out about 4 turns for it to idle somewhat decent. The engine has about 2000 miles since Overhaul and it has an RV cam in it. I Had the carb apart VERY thoroughly cleaned and Made absolutely sure all passages were clear. Still same result.I have power brakes checked for vac leak and None. I am at my witts end at what to do?
Timeing is set at 14 degrees BTDC and Yes the vac advance is hooked up to the Vac port on a 2100 series motorcraft carb. Front port Choke side of carb I have been told to change the jets to a larger size. The ones used are a "55" and was told to go with a "64". Have not tried that yet as I have no jets on hand to try
Main jets shouldn't be involved in idle. If they are, you have the throttle plates way too far open for some reason.
Does the choke go from fully closed to fully open too fast maybe?
Is it electric? Is it the stock choke cover that's supposed to get it's voltage from the alternator and not full 12V battery, and it's hooked up to battery voltage?
I'm not sure of the cutoff (if there is one) but usually the choke was connected to the stator terminal of the alternator. I'm not sure if that changed.
But that aside, you can try rotating the choke cover one way or the other to delay the point where it opens the choke. This way, it won't open the choke so fast.
I actually did try enriching the choke but I always seem to have better results with more advance on the timing. It sure does Like Advanced timing, Runs Better smoother more power better gas mileage and idles better. Advancing the timing is really the only thing I have done that made the biggest difference.
I am a bit confused tho about where the choke should be hooked up I have read that the Stator Terminal only puts out about 6-7 volts would be enough to open choke but would take a long time. Most aftermarket setups are 12v. I was told stator voltage is AC current. Mine is hooked to 12 volts Key on position. I need to find more info on it before I switch
I had always hooked my distributor up to intake vacuum until I purchased a 4160 Holley. Now I have it hooked to timed port and had to bump timing up a little but now idles like a dream when chokes pulls off.
I am a bit confused tho about where the choke should be hooked up I have read that the Stator Terminal only puts out about 6-7 volts would be enough to open choke but would take a long time. Most aftermarket setups are 12v. I was told stator voltage is AC current. Mine is hooked to 12 volts Key on position. I need to find more info on it before I switch
What year is the truck, and is the carb original? See if there are any part numbers on the choke cover and report back.
The stock setup was to hook the choke to the stator terminal of the alternator. It wasn't meant to get 12V. It could be the reason the choke comes off too fast.
The Truck is a 1973 F-250 with a 390 now original motor was a 360. The carb is a motorcraft 2100 "D3TF GC". There is a Number on choke cover,"5110C" The electric choke is currently hooked to a keyed power source 12 volt.
It was actually on that carb when I bought the truck. The Hot tube setup was still there, but when they dismantled the engine the tube broke was rusted and I did the research and found you dont need the hot tube setup if you are using a electric choke