manual choke problems....

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Jul 24, 2006 | 11:53 PM

62Cole

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manual choke problems....

hey guys need a lil help here....i have a straight six 223 with a single barrel holley hooked with an elsctric choke...now my problem seems to be that when i start the truck cold it runs great at 800 rpm's with the choke a lil pulled out and then when she;s warm great at about 650 rpm's with choke pushed all the way in (not pulled out at all). then nit runs great and steady like this until i do a lot of driving in the heat...like an hour or two of driving and it's idle drops down to about 400rpm's and will die if i do not pull the choke out a lil and bring it back to 6oo or 700 rpms....it's not overheating or anything like that in the heat but i can't figure this one out....am i operating the choke wrong or is there some other thing to blame....

Jul 25, 2006 | 12:10 AM

airharley

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From: Escondido, CA

Sounds to me like you have a fuel problem. The intake sits on top of the exhaust manifold if memory serves me correct. Been a few years since I owned a 223. There is a thermo valve that directs heat to the bottom of the intake under the carb. Check to see if this is stuck wide open. If it is then it could be heating the carb to the point fuel is starting to boil in the carb which gives a really crappy idle after running for a while. A solution to this would be to put a non metalic spacer under the carb if this is the case. It will cut down on the heat transfer. I ended up working the valve loose with a pair of channel locks and easy-off oven cleaner. Once it was free I closed it since I lived in CA, well the first time.

Jul 25, 2006 | 08:08 PM

R Pope

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Pulling the choke on the warm engine is just engaging the fast idle cam, allowing more air in and speeding up the idle. Set the idle mix and speed screws with the engine warm, the problem should go away.

Jul 25, 2006 | 11:29 PM

62Cole

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i already set the mix and idle speed with the engine warm....does this after an hour or two of heavy driving in hot weather 75-110 degrees.....not after just warming up

Jul 26, 2006 | 08:15 AM

R Pope

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Your first post says "electric choke" , then you describe running a hand choke .??????
The problem could be a needle and seat leak , or as others have said, the heat riser stuck. If it's not the original carb, it could be a jetting or power valve mismatch.

Jul 27, 2006 | 12:10 AM

62Cole

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my mistake i meant manual choke...thinking too fast for my slow typing..sorry for the confusion

Jul 27, 2006 | 07:10 AM

William

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From: Sun River St. George

On the exhaust manifold is an exhaust heat riser. This is a flapper valve, counter weight and bi-metal spring. The heat riser closes when cold and opens when hot. If your heat riser is stuck shut it will overheat the manifold and boil out the fuel. Check by twisting and shooting some carb cleaner on the pivot points. If you still have points consider replacing them with a Pertronix Ignitor and their coil. Check timing with a light and check idle vacuum with a vacuum gage. This could be as simple as raising your curb idle a bit!