I think I have overlooked the obvious and have started to confuse myself, so I need help. I was helping a friend today work on his 1967 chevy c10 pickup with a fuel smell issue he was having. It is a 67 chevrolet c10 with a 250 straight six and 3 on the tree. It has a 1bbl rochester carb with manual choke. We found the throttle shaft leaking so bad that it would actually squirt out fuel every time the throttle was snapped. We tried to rebuild it, but found the throttle plate damaged along with other things, so we decided to s**** it. He decided that is was best to buy a rebuilt one from carquest (made by holley) and have me put it on. The first one was destroyed. Who ever rebuilt it left parts out, overtightened the plug where the fuel filter goes and flared it out and heli coiled the threads for the fuel filter plug. We sent it back and got another one. The second one is on the truck, but now it won't idle unless the choke is closed all the way and continues to pop through the carb when you open the choke and try to gas it to keep it running. I was thinking there was a huge vacuum leak. We found the intake gasket leaking really bad so we replaced it. Then we found the throttle shaft leaking and I was able to seal up the one end with the plug with epoxy, but the other end has the linkage and I can't do that. I am at a lost on what to do now. Any help is appreciated. Here is a list of what the truck is doing right now: 1. Hard to start cold/hot 2. Won't stay running unless choke is all the way to half closed. 3. Won't idle under 1500rpm by itself. 4. Pops through carb occasionally. 5. Idle raises when carb spray is sprayed at one end of throttle shaft. 6. Idle fluctuates occasionally. Does this sound like a huge vacuum leak? Is the throttle shaft leaking severe enough to be the giant vacuum leak? Please someone help me or give me tips on what I can try. Thanks, Jeff
All throttle shafts leak a little because they are metal on metal,even when they have a new bushing.The leak is magnified because it's so lean. Are you sure the base gasket is the right one and sealing the bottom? There is a plug inside that may have fallen out that will cause this problem.The old story about parts store carbs is to get the fourth one on the shelf cause that's one that works.
You shouldnt have to mess with a one barrel right out of the box, that one is bad, call these guys: http://www.carbkitsource.com/ Carb Doctor,
A quick check for serious leaks at the throttle shaft and the base is to get a hand oiler (the kind with the trigger and short spout that allows you to put small amouts of oil on selected spots). Put a little Mystery Oil into the oiler and, with the engine running, squire some oil on the ends of the shaft and see how the idle is affected. Then do the same thing around the base along the gasket edge. If the engine smooths out some, you've found at least ONE bad leak. The Mystery Oil won't hurt the engine if it's drawn into the combustion chamber. As a matter of fact, If you put a couple of ounces of Mystery Oil into your gas tank (per 10 gallons) it'll help protect your valves and valve seats from the lousy gas at the pumps today. Especially that ethonol ****.
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