The Stovebolt Site Forums The Shop Area Engine Shop 63 c-10 carb problem rochester model B

Ok, truck is full of gas, fuel pump is working fine, vacuum lines good, fuel filter clean. Truck will only run with choke cable pulled out all the way. Trash in the carb is my guess. Any input. Truck has 230L6

I think it's time to take the carb apart.

Yeah, thats my plan tonight. Is there a "common" place where trash might accumulate in these carbs?
And nice looking GMC love the colors

Checked carb, all seems ok. Still having the same problem. Talked with Holley and they thnk that its an intake gasket leaking. I plan to replace it this weekend just to rule it out, reclean carb again, replace fuel filter/air filter, check spark plugs and a couple of prayers. Dont know what else it could be.

You can check for an intake leak using a propane torch. You just move the unlit torch along the intake, and if the propane gets sucked in, you'll hear a difference in the engine. By checking the carb, do you mean you took it off the engine, and opened it up? Often there is sediment or other junk in there that can clog up the works. A "kit" for the Rochester B carb is cheap. Just follow along in the shop manual when you rebuild it, and make sure you put the little balls back where they should be, and set the float level to where it should be. You may, or may not have a fuel filter inside your B carb. Just keep at it!

Yes, I took it off and completely disassembled. Carb was rebuilt by Holley 6 mo ago. Everything looked fine, put it back together and still having the same problem. Truck only runs with choke cable pulled out 2 in. I have two filters, 1 on the output side of the carb, and one inside the carb.

Well, checking or pulling the intake sounds like the next plan! Your timing is set right?

When you put the carb back on, you set the mixture and idle speed?

sounds to me if the intake is not leaking it would be the set screws havent been properly preset. Also when you pulled the carb apart did you use compressed air to make sure all the passages are clear of any obstruction. I am sure you have already done all this but double check

No, I dont have a compressor. Im taking the truck to my fathers this weekend, he has one. I plan to pull carb and reclean it, then reinstall. I want to rule out the carb before I have to change an intake gasket in 30-40 degree weather outside.

I left the mixture and idle speed screws alone when I pulled the carb off the 1st time. This time I will pull both and clean good again. What are the factory settings for the 2 screws?

I left the mixture and idle speed screws alone when I pulled the carb off the 1st time. This time I will pull both and clean good again. What are the factory settings for the 2 screws? Also...what should my engine be reading on the vacuum guage at idle? How many inches?

You'll have to look in the shop manual for that info. Your engine is much newer than anything I've had.

Reset everything to fact specs on carb when took it off this weekend. New intake/exhaust gaskets, new fuel/vac lines, fuel pump, and installed a fuel pressure guage (4psi steady) and still at same problem. Holley rec's that I exchange float and see what it does. They think that the float may be the issue.