1986 350"M" Carb Problem?? Black Exhaust/Strong Fumes

Discussion in 'The Garage' started by Dave1, Dec 28, 2003.

  1. Dave1

    Dave1 Registered Member

    Jan 4, 2002
    Likes Received:
    Winter Springs, (Central) Florida
    1986 350\"M\" Carb Problem?? Black Exhaust/Strong Fumes

    My 1986 GMC C2500 4WD P/U has a stock "M" series 350 with 200K miles. The engine has been rebuilt, don't know about the carb. Lately I have noticed alot of strong exhaust fumes and am seeing some black exhaust smoke at idle. The dual (no caty converters) tail pipes are also black.

    I replaced air and fuel filters, plugs, wires, cap, rotor, and module. It runs better but still has some black exhaust and strong exhaust fumes. Would it be the carb that is causing the exhaust smoke and strong fumes? Other possibilities??

    I asked around a while back and the price to rebuild the old carb is fairly high and I would still have an old carb. Would it be better to spend extra $$ and buy a new one? If so, what is the best brand/model relacement carb??

    Thanks, Dave
  2. R72K5

    R72K5 Banned

    Mar 5, 2001
    Likes Received:
    central IL
    Re: 1986 350\"M\" Carb Problem?? Black Exhaust/Strong Fumes

    that is the carb loading up, or the choke being stuck shut on you,
    do you know if the choke is operating correctly, have you observed it from a cold start all the way up to warm idle to make sure it opens up on its own completely once it is fully warmed up ?

    i had the same thing happening on my 83 with code M 350 engine when i first got it and so i disassembled carb and cleaned her out real good and used bucket of carb acid at the garage and put in rebuild kit from local parts store and truck is all better, runs like it is brand new /forums/images/graemlins/laugh.gif i have disasembled and rebuilt alot of rochester and carter Q jets to date and they are easy for me to do, they are not complicated at all to me, even you could do it if you take your time and watch everything, theres only a couple minor tricks.

    i would repair/rebuild your Q jet for 25 bucks plus you get the kit, the kit will be about 27 at auto zone, the carb would have to be comeplete and not have throttle shaft bushing slop/play

    is that good ?

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