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I think my fuel pump (5yrs old) is going out I’ll drive around and it will bog down as if I’m running low on fuel, I will stop and then take off slow with no prob but then it will do that’s same thing. I’ve been told it’s the fuel pump or crank shaft is worn out and won’t activate the manual fuel pump correctly. I’m thinking of going with an in line electrical fuel pump. Any thoughts advice? I also have a 351 Windsor that I might just install but my 49 is all original with an original flathead 6 with a 3 speed on the floor.
I agree, probably not the fuel pump, probably fuel starvation. The lines are either blocked with crud or the lines are cracked preventing proper suction or some similar defect. Definitely does not warrant engine replacement and probably not even fuel pump replacement. Could be the pushrod as discussed earlier as well. All the above are simple to remediate.
I swapped filters and cleaned them out could be clogged lines since fuel was running low. It’s still doing the same idles fine but if I keep it revved for a bout 5 minutes the in line filter dries out and the truck turn off. I wait a few seconds and it starts right up
I've had to remove my gas tank and have it boiled out at a classic radiator shop. The tank had so much crud that it blocked the outlet on the bottom causing a fuel starvation problem like yours. You can temporarily correct this by blowing (low pressure) compressed air into the tank (neck cap off) from the line at the filter.
I had a problem with not enough fuel getting to the carburetor. It turned out there was an air leak in the seal between the body of the fuel pump and the glass reservoir/site glass. I replaced the cork gasket creating the seal and was back in business. My fuel pump was relatively new, and it was surprising that out of the blue the gasket failed.
You could remove the fuel line from the tank at the pump. Hook up a rubber fuel line at the pump and place the other end into a gas can. If it runs fine then you know somewhere in the supply system is your problem. Either plugged or air is entering at a fitting causing the pump to loose prime. If it still doesn't run then raise the gas can to gravity feed the fuel pump. If it runs then either the fuel pump is weak, rod is worn out or it is loosing prime by an air leak as 52 USCG Panel suggested. I installed an electric fuel pump in my OT cars flathead and it works well. Nice looking truck.
Great looking truck. If you ever switch to an electric pump, get one with the correct pressure. All electric pumps are not the same. To much pressure will override your carb.
IMHO, you shouldn't be considering an electric pump until you verify the rest of your plumbing is functional. But our flatheads should fall be between roughly 2-4 psi, definitely not above 5.
This is what the supply pressure looks like with an electric pump and a Holley 12-804 regulator. With a mechanical pump you'll see the needle jumping around with each cycle of the cam. Just one of the many benefits to going electric.But you still need clean lines and a clean tank.
The carburator does not care about the pulses from a mechanical pump or more steady stream of the electric. It just goes into the float bowl reservoir and makes no operational performance difference and therefore is not a quantified benefit one way or another.
Are you sure your tank is not air locked? As fuel is drawn out, air needs to be drawn in to replace the fuel volume. If no air gets in, a vacuum is formed and eventually the fuel flow stops. If it sits for awhile or you remove the gas cap, the air is replenished and it will repeat this process.
