My buddy's 51 chevy 235 I6 was a real strong runner until recently, suddenly it starts idling rough and likes to stall when any attempt to drive away is made. We have since changed the points as well as looked at the jets and the plugs. Any guesses? Also it has been converted to 12v and I thought that didn't matter as far as points were concerned, am I wrong? Thanks!
Points are too stupid to know or care how many volts the electrical system runs on. Eary Chevy sixes were known for burning valves, so do a compression test and see how things stand there. Also, spray some carb cleaner or light oil along where the intake mates to the cylinder head and see if the idle changes, indicating a leaking gasket.
did have a problem with my 53 when it had the ol' 235 in it..mine turned out to be the carb..and some junk that got plugged in the low speed jets..also when i thought i got it cleared up it had more **** in it..so i took it off and rebuilt it, and changed the fuel filter..it was ****in rust up out of the tank..it snow balled into cleaning out the tank replacing the fuel pump and filter and gaskets on the carb..ta--da it fixed it..really need more information than what you have said to be sure..but you might wanna check into **** in the carb or **** already in the carb and get it cleaned all out good before you move on to other things.
12 volts will fry points unless a resistor of some type is put in supply going to the plus side of the coil. Good luck
Thanks for the responses! I did check for leaks with carb cleaner at the manifold, carb base, and vacuum advance. It does have a resistor on it. The fuel in the filter looks kinda milky and he did recently drop the tank to put in a new sending unit and blew out the lines with a compressor and it was soon after this (a day or two) that it began to act up. The inline filter is after the pump and is relatively new and seems to be working well you can see the difference in the gas on the other side going into the carb. My compression tester seems to have disappeared but the plugs look ok just a little bit darker than I'd like to see but not alarming, could it still have a burned valve? I will be doing a compression test today and likely removing the carb (if I can find a kit today) Thanks for the tips! This engine appears to be bone stock except for the 12v upgrade, and was very smooth and surprisingly torky.
It's probably water or **** in the tank. If he had the tank out jostleing it around it might have loosened up the rust deposits inside. My old 63 Chevy truck was bad about condensation forming in the tank. When it got enough in there it acted the same way as his. Pull the tank and drop a few big ball bearings in with a gallon of lacquer thinner, shake it like crazy and then flush with water. Put it in the sun to dry completly then reinstall.
Yep, my thoughts exactly. Or, sounds like a bad accelerator pump maybe? Do those old Rochester carbs have accelerator pumps?
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