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Discussion Starter · #1 ·
Just reçently bought a 69 GMC C15. Stock 307. 350TH, 3:70 12 boltr rear end. Has been running great. Today ran up to them electrical supply house and as I was leaving it cut off at a red light. Had to press the accelerator and it finally cranked. Cut off a few more times on the way home. If I put it in neutral at the light and pedal it she continues to run. Feels like it's flooding out to me. My question is what is the easiest carb to work on. As far as mixture adjustments that is a reliable carb for a daily driver on a stock motor.
 

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If your stock you probably have the best one on there now (Q-jet) Check your filter it should be in the carb where the fuel line goes in.
 

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Discussion Starter · #3 · (Edited)
I am pretty sure the motor is stock, it has a Holley 600 carb on it. I am going to give it a shot and try to adjust it when I have some time. I am very familiar with the Qjet. The more I think about this I wonder if it is the carburetor. Truck cranked up earlier this morning idled about two or three minutes and I headed up to the Church. It sat out side for two hours and I drove it home. Twenty minutes later I went to the electrical supply house probably a 6 mile drive. Was inside maybe 15 minutes and then as I was leaving sitting at the red light it stumbled and shut off. This truck has and HEI distributor, I wonder if the pick up could be going bad? What do you guys think?
 

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If its a Holley 600, check the side sights on the fuel bowls, unscrew it while running, fuel should barely be trickling out, if its flooding then the fuel will pour out of the hole, either adjust the float top screw with jam nut, counter clockwise to raise the float. If it continues you`ll need a new needle and seat assembly, it could be front or rear bowls or both...
 

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Discussion Starter · #5 ·
Ok finally had time to look at the truck. Checked the float level, everything looks good. Have not had the problem happen again until Thursday night. So Saturday I pulled the air cleaner to make sure it was not a choke problem. Everything with the choke functions properly and looks good. I did find what looks like oil not fuel in between the runners on the intake manifold. Does anyone have a clue where it might have come from because I see no clue of where it came from.. Middle two runners right beneath the carb on both sides.
Thanks
 

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Valve covers on the small block chevy are hard to keep from leaking or the oil is being pushed up the the intake manifold bolts right there, wipe it up and watch while engine is running or take for a short run and look at it again, are you running a PVC valve from the right valve cover to the back of the carb or intake manifold…?
 

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If your running the old stock tin valve covers they could be leaking. I can't remember the last time I put a set of them on anything but engines on a stand.
 

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Chevy v-8s are notorious for getting oil in the center of the intake at the exhaust crossover.Oil migrates up thru the 4 center bolds and puddles there.Try pulling those bolts and use some sort of thread sealer or silicone and see if that doesn.t correct it.As for valve covers,I have had best results using quality cork gaskets and smear a light coat of silicone one both sides.This also makes it easier to remove the old gaskets when they need replacing.Do this sparingly and use some good spreader bars to retain the covers.Gm used to sell a kit that I found to be the best quality however other venders make them also.For the stumble and dies check the wires from the pickup coil to module,give them each a tug to see if they are broken.
 

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Discussion Starter · #9 ·
Thanks guys I checked the valve covers doesn't look like its coming from there. I will check the manifold bolts and put some sealer on them. I adjusted the air/fuel mixture today and it smoothed out I will see how it runs tomorrow. Thanks for the advice.
 

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Discussion Starter · #10 ·
OK. I pulled the manifold bolts and put thread sealer on them. So far so good Thanks. No I am still having what feels like carb problems. I have checked the float level and they are perfect. I have checked the choke it closes when the accelerator is open and the choke opens like it should as it warms up. I adjusted the air fuel mixture Monday till it was running smooth and it ran fine yesterday. Got in it to go pick my daughter up from school today let it run a few minutes to warm up and when I got to school a ten minute drive it was running sluggish like it wants to shut down. Very sluggish idle. It only seems to do it after it warms up and it also sounds like it is spark knocking after it warms up. It is a stock 307 with HEI distributor, Holley 600CFM. What gives?
 
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