David Downs

Interesting thought. Can you offer more details on what to look and test for? New coil? Would a weak spark cause fuel starvation?

Sorry I wasn't clear. I will drop the tank and have it cleaned to make sure its not a tank pick up line issue. Has anyone installed a fuel check valve? This could help keep the fuel closer to the carbs with less cranking.

The pump spacer you posted is the exact one I purchased. I went back to the garage and manually pumped fuel through the entire system. I confirmed that fuel is pumping to the float bowls. Once I pumped fuel through the system I let it sit for a few minutes to see if the fuel would drain back toward the tank. This time the fuel remained in the engine bay fuel filter. So, I cranked the engine and she fired up. Now I'm even more puzzled because this is likely an intermittent problem. My next thing is to drop the tank and make sure I'm not picking up debris at the end of the pick up tube.

The first video is the engine turning over to show that the mechanical fuel pump cam lobe is functioning. The second video was me pumping the pump arm manually to pull fuel to the filter. Third video shows the fuel in the filter draining back to the tank filter after letting it sit for about a minute.

Yes, removed cover and cranked the motor over. Arm is moving, pump is new (3rd one), and the pump spacer is new as well. I will upload a few videos but not sure they will work since its from my iPhone. FullSizeRender.MOV IMG_7624.MOV IMG_7623.MOV

No fuel to carbs. If I crank the engine long enough fuel starts to pull to the filter. I can spray carb cleaner in the intake and she will fire.

I have replaced and checked everything related to fuel except dropping the tank. Replaced and checked all fuel lines, installed fuel filter at tank, blew air through fuel lines (including return), pulled vacuum on the metal fuel lines (held vacuum), drained tank, overhauled SU carbs, and can't keep fuel in the engine fuel filter. I removed the valve cover to check on the fuel pump cam lobe. I'm able to pump fuel by moving the pump lever by hand at the cam. Is it possible that I'm not getting enough lift from the mechanical pump cam lobe? Or is there an issue with Delphi pumps? There is plenty of fuel in the filter I installed at the tank.