Ok, so we fixed the shackle, r and r'd the tank to replace all the cracked and leaking file fill and vent hoses and put it all back together but when the tank is half full, it no longer picks up. We are not pumping fuel.

I thas a 23 gal after market tank and I know there is 7 gallons in it now.

any ideas? I am stumped. When we pulled the tank everything looked good inside. Works fine when full, just dies when we reach half tank.

Thanks

You might have the pick up line and the vent line backwards.

You don't need a return. Mount the pump as close to the tank and as low as you can. That will make it easier for the pump to work and will pressurize most of the fuel line minimizing vapor lock tendancies.

sometimes a line can get a crack in it and will suck air when the pump is running. I had this happen to me more than once and it turned out to just be a short section of rubber fuel line was worn out and ruptured.

Some simple things.

Disconnect hose at the carb, extend with more hose, then put the end into a big glass jar. Crank the engine a few times to see if gas is coming through. Let it sit for a while and see if it has water in it.

If you have a vacuum/pressure gauge, attach that and crank a bit to see what sort of fuel pressure you are getting.