Ideal fuel pressure for 1050 Dominator?

Discussion in 'The Mixing shop.' started by BUICKRAT, Aug 21, 2018.


    BUICKRAT Torque Rules!

    I have heard that these carbs don't like a lot of pump pressure, 4.5psi max. Correct?

    Having a flooding issue after warm(hot) soak, even at 150 degree engine temp. Fuel seeps/runs out the pump jets.

    Mobil pump gas, 93 octane.

    Would love some input.

    Thanks, guys!
  2. Bens99gtp

    Bens99gtp Well-Known Member

    I don't see why these would be any different than any other base holly carb. I run 8 psi when I had the 4150 on, 8 psi when I ran then sv1, 8 psi with the dominator.

    When you say fuel comes out the pump jets........are you referring to the squirter?

    You have to remember the fuel in the float bowl is not under any pressure, so it doesn't matter if you are running 4 psi or 8psi. All the psi does is help determine how fast the fuel will be replaced into the bowl once the needle opens.

    The fuel in the accelerator pump us sucked into the pump housing after the pump works and is returned to its relaxed state. There is a 1 way valve......normally a red flap of rubber that seals when pumped to keep the fuel from going back up into the bowl and out the pump circuit but unsealed to allow fuel to be replaced and ready for the next time it's pumped. Again no pressure in this circuit. There should be a gasket both above and below the nozzle. And there should be a needle shaped check valve below the nozzle. This can cause fuel to be sucked out the nozzle when running.
  3. Briz

    Briz Platinum Level Contributor

    The 1050 on the regal stays around 7 PSI. Only leak I had was the threads stripped out of the float adjustment on the rear bowl and had to be replaced.

    DEADMANSCURVE my first word : truck

    same basic floats , needle n seats etc as regular holley's . I always recommend 5.5 - 6.5 lbs fuel pressure as a start u point .
    pic #1 - pump nozzle - guessin a little here , if your fuel level in bowl is too high I guess fuel could creep up towards nozzle via the pump shot passageway and maybe be drawn out some from a strong plenum signal ? not so much with the newer rubber seal maybe but more likely with the older steel check ball style .
    pic #2 - booster ( main feed ) , pic #3 - full transition slot , pic #4 - close to correct transition slot at idle ( should really be about half that ) . if you are talking about fuel leaking out of booster and if your transition slot is open too much ( throttle blade setting ) then what may be happening is that your idle circuit is being bypassed and the signal is pulling fuel out of booster at idle . if this happens then usually your idle screw setting will make no difference , it's running off of the main circuit .
    I hope that I explained that ok . and that it makes sense .

    Attached Files:


    BUICKRAT Torque Rules!

    Thanks for the replies. Del, the fuel is coming out the pump nozzles with the engine off. A couple times it squirted out the bowl vents while running when the motor was at temp.
    This problem started after 3k miles of trouble free driving. At first it would happen only when the motor and outside temps were very warm, actually flooded so bad the car quit.
    Now it seems to be getting worse and happening at lower and lower temps.

    DEADMANSCURVE my first word : truck

    well if its coming out of bowl vents and nozzle I would check float level and maybe suspect heavy float(s) and or maybe needle n seats stuck open . maybe something got in there and is keeping the needle n seat open a little ?
    personally I would yank the carb , get it on the bench , grab a couple bowl gaskets and pull 'em and strip the bowls down and inspect everything .
    the temp thing is a little weird though . and maybe not even relevant , just a happenstance thing ?
    Last edited: Aug 25, 2018
  7. DasRottweiler

    DasRottweiler -BuickAddict-

    Steve, is this a new ,outtada box carb, or a used one?
    Maybe a damaged float , as Del said, heavy float. Dunno, I ask you when I need help! GL Jim
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    My 1972 Q jet and my 1000 DP have absolutely no problem with the 8-9 psi from my mechanical CV Products Fuel Pump. Sounds like a weak float or damaged needle/seat.
  9. hugger

    hugger Well-Known Member

    Needle is probably got a groove in the tip, as Del said it's going to be one or the other, stab a fresh one on there and set seat to 3 threads showing. And go from there
  10. Bens99gtp

    Bens99gtp Well-Known Member

    I have seen the stem on some of these newer needles and seat being shorter, forcing them to need to be screwed in farther, the boat I just did I had to live with a float level that was higher than I wanted, physical would had the set so far in that the adjesting nut would not of held the flats

    DEADMANSCURVE my first word : truck

    you can bend the small tab on the float arm inside the bowl a little to give you more or less needle n seat adjustment range depending upon what you need . also stay away from the generic kit needle n seats that use the middle screw as the float adjustment , they use an o-ring to seal down inside under the lock nut instead of the 2 flat gaskets . heard a couple bad things on those .
    edit : correction , that is for the side hung bowls . on the center hung bowls you just need to CAEFULLY bend the float arm at the float end .
    Last edited: Aug 27, 2018

Share This Page