'69 350-2 misbehaving when hot

Discussion in 'Small Block Tech' started by ThinRedPaste, Nov 8, 2017.

  1. Mark Demko

    Mark Demko Well-Known Member

    When the engine is cold, it can use the extra fuel your carb is dribbling into the engine, same as the choke being closed or nearly so.
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    How about the fuel pump? How old is it? A weak fuel pump can lead to a low float level, and the problem can come and go. I remember that from the 72 Skylark 350-2, that was my first Buick. Does your fuel pump have a vapor return line? If so, is it hooked up and functional?
  3. ThinRedPaste

    ThinRedPaste Member

    Fuel pump was on the car when I got it a couple years ago. It does have a return that as far as I know is working. I wouldn't be surprised if it was the original pump. I also read on a different forum about a vent on top of the carb sticking shut and causing similar issues. I'm going to check that out tomorrow, assuming it doesn't rain all day again.
  4. Mark Demko

    Mark Demko Well-Known Member

    If you can, and its not raining on you, take pics or a vid with the air cleaner housing off of the carb and the car fully warmed up (after driving for awhile) and idling.
  5. ThinRedPaste

    ThinRedPaste Member

    That vent was stuck. now it's unstuck, but i couldn't see it actually doing anything once the car was warmed up. the problem did seem lessened, but not cured. Now it has to be in gear and sitting at a light for the idle to get bad.

    i took a little video of it idling. I'm aware i have an exhaust leak. I'm also aware of how mickey mouse that **** on the fuel line is.
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I'm not sure what vent you are referring to. The main vent on that carburetor is right there inside the throttle bore up top. Unless someone stuck something inside of it, it would always be open to the atmosphere.

    One thing I noticed from your video, the choke vacuum break appears to be defective. With the engine running, vacuum should pull the link all the way in. Yours is extended. That means the diaphragm is defective. That could potentially create a small vacuum leak.
    alec296 likes this.
  7. ThinRedPaste

    ThinRedPaste Member

    Suddenly this is not a high priority anymore. My th350 is about to die. Full of fluid but slipping and dropping out of third. Anybody got a line on a 200-4r for cheap?
  8. alec296

    alec296 i need another buick

    Going to be some work to convert that 2 barrel to accept a 200r4 tv cable. And you will really want a deeper 3 series rear gear or it will load up under 45 in overdrive.
    300sbb_overkill likes this.
  9. 67skylark27

    67skylark27 Brett Jaloszynski

    If you end up doing the tranny swap feel free to pick my brain. I had to fabricate a tv cable mount
    on my 2 barrel 300 before I did the motor swap.
    alec296 likes this.

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