73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: thelincolnguy on December 05, 2015, 10:46:13 AM
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Just bought an 85 c10 that the previous owner had installed a 350 in with a brand new carb. I got it home and when i went to run it, the choke was zip tied wide open. So i cut the zip tie and wired the electric choke to ignition power. Went to start it, it runs at like 2000 rpm closed choke. As soon as u hit the gas it dies. Dont wanna spend a lot of time or money on it. Just want it to run so i can get motivated to bolt up the torque converter and put the drive shaft in.
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The stock 1985 choke runs through the oil pressure switch. This keeps the choke from opening without the engine running. It'll work the way you wired it.
If you leave the ignition switched on the choke should heat up and open. If it doesn't it's adjusted wrong or the electric heater has failed.
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I watched the cd that came with the carb. If i unhook the choke linkage and turn the key, the plunger should move right away correct? If so then it just needs to be spun to the right orientation
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What kind of carb?
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Edelbrock 600cfm i believe.
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Just bought an 85 c10 that the previous owner had installed a 350 in with a brand new carb. I got it home and when i went to run it, the choke was zip tied wide open. So i cut the zip tie and wired the electric choke to ignition power. Went to start it, it runs at like 2000 rpm closed choke. As soon as u hit the gas it dies. Dont wanna spend a lot of time or money on it. Just want it to run so i can get motivated to bolt up the torque converter and put the drive shaft in.
This could be real simple. There are two idle screws, fast idle and normal idle. I could make an Edelbrock do that if I set the high idle way too fast and the regular idle way too slow. It could be that simple.
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did it run with the choke zip tied open?
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I heard a lot about the idle screws. And yes it ran with it zip tied open.
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I'm having the same issue with the same carb /engine. Did you check for vacuum leaks? If the tuning doesn't help or the truck dies when you open it, thats most likely the cause. If my choke opens even a little, it'll kill the engine. Also if its a new carb, theres a chance the guy before you didn't let the gasket seal right between carb and intake, which would cause a vacuum leak. Best way to test would be to take carb clean and spray around the intake/carb and vacuum lines, if the engine changes idle speed at all, you've found the leak.
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i forgot about this post but like hutch said have you checked for vacuum leaks? although im not sure how well thats going to turn out since with the choke open it ran. but its still early and im not 100% thinking right. did you try and tune it?
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I was wary of the seal since the previous owner really didnt know anything about engines. He just bought a carb and put it on thinking it would make the truck turn into a bar of gold. And i have not checked for vacuum leaks. The underhood of the truck has been gutted and only what was necessary was put back in. (Not by me)o once the weather gets warmer i will get back onto this project.
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do you know how to set the idle mixtures ? and have you done that yet ?
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Carb only runs on full choke, but you say it also runs when the choke was wired open, both?
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The choke was tied open when i bought it. I cut the zip tie and wired the electric choke. It only runs completely closed. And no i havent adjusted them yet. The only carbs im good with are kohler, briggs, and honda power equipment. Im a diesel mechanic by trade
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at the front of the carb near the bottom theres 2 screws - turn both screws to the right (closed) be carefull to just lightly seat them then run both screws out to 3.5 turns each
on the choke side you should see another screw phillips , that is spring loaded and is easier to get at with the choke closed and fast idle engaged - turn that screw left a full turn ( sounds like someone messed with it and went too high )
on the throttle side is another screw flat blade - unscrew it until the scre doesnt touch the throttle arm -then turn it back in until it makes contact and go a full turn more in
start it up and turn the idle screw on the throttle side in more if needed
time how long it takes for the choke to fully open and post back
this just a ball park test the choke might be set too rick or too lean for the current weather assuming its winter where your at
start there and let me know what you find
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Sweet thanks for giving me some ground to build on. Blizzard coming this weekend here in maryland so ill dig into it once that passes. Is there a starting place to turn the electric choke?
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for choke adjustment - just loosen the three screws ,while your loosening the third screw put your thumb on the black disk it might spring back or spin to the left
- let it unwind (there is a coil spring behind it - last guy might have wound it way up tight
-engine off and cold - hold the throttle wide open if your not familiar with setting the fast idle cam on high step or have a friend hold the it open -
while you turn the black disk counter-clockwise slowly until the choke plate just closes - you'll notice at the top of the choke housing some small notches ,1 big notch and more small notches - you can set it about the 1st small notch to the right of the large notch that will be close - the more counter-clockwise of the large notch you go the longer the choke is on
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If I read it correctly, you said it only runs (assume idle) when the choke is fully closed. Also assuming when you open the choke it will not idle, either when its cold or hot. If it will not idle when the choke is off or open, you more than likely have a vacuum leak.
Check every port on the carburetor, on an Edelbrock there are usually two small ones on the front and one large one on the back. If those ports have a vacuum hose connected follow them to the source and make sure there are no breaks. You can also try plugging all the ports at the carb and see if will idle. If so, then add one hose back on at a time until it runs bad, then you can check that hose or source for issues.
I usually start with the idle mixture screws at 2 turns out from bottom. A vacuum gauge can help a lot with this adjustment. You want the highest steady vacuum reading on the gauge. If your engine is stock you should be somewhere between 17-20 inches.
Another thing about Edelbrocks......the floats are almost ALWAYS set wrong from the factory. I have not opened up an Edelbrock yet and not found them set wrong.