In this swap I did nothing to the engine but put a new cam in it, and adjust the valves. Everything else has 298k on them.

Engine starts hard after it sits, Needs primed up then it pops off every time. I air tested the lines I have made, all are tight. I ran the return line just up to the filler neck, and welded a bung in there so it just dripples back into the fuel tank.

Could it be losing prime if thats just in the air, I noticed I hear the fuel drain back after its shut off. Do I need to put a line from that bumg and have that line in the fuel to keep the siphon in the line?

Also I told the customer to drive it, and not all the bugs, Ill take care of them as they happen. He told me one time it wouldnt shut off, I told him to tap on the fuel shut off solonoid, Might be hanging up.

All in all he is happy, but were gonna have to address the starting issues.

 

I think your return line may be sucking air ? they go back to fuel tank reg ? I would think it's getting to the air easier and that's your problem ?

 

Thats what I was thinking. I told the guy to put a 1/4" hose and a heavy duty nut wired tot he end of it to weight it to the bottom of the tank. That way it cant suck air. There is about 1.5" of 1/4" bung sticking inside the fuel fill neck, and it shouldnt be to tough getting that hose on there.

I still think he has a fuel shut off solonoid sticking also.

 

I don't think the return lines draining into the filler neck are the problem. That is how I ran mine and have not had any problems for the past 40,000 miles. I recently got around to doing the rear tank, adding a selector valve to switch between front and rear tanks and route the return to the proper tank, and have not had any trouble with all my added connections.

I would check from the lift pump forward for a place air can be getting in,