What am I missing here. Want to put a Walbro 175 back into a 357XP. Cleaned and rebuilt the carb and I have a leak through the pump side gasket. I have a couple HDA 199’s that are doing the same thing. Whether at 15 psi or 8 psi. All three are leaking bad kits? Using Walbro OEM. Bad cleaning? Too much torque on the screw; not enough?
Are you checking the pop off pressure for the main needle and diaphragm. Try checking the order in which you put the gasket back in place.
I thought it’s diaphragm first on the pump side but gasket first on the metering valve side. I’ll double check that. that was my intent, to check the pop off/valve seating. But I discovered this leak on the pump side. Noticed it when it wasn’t passing pop off so I added some fuel mix to lube things up and I started seeing that leak under pressure when I pumped it up. Looks like the valve is holding but can’t really tell until I get this part fixed.
Yes you are correct it is diaphragm first on the pump side. I was thinking of the metering side when I said that. You know I do not usually pressure check my carburetors when I rebuild them. They either work or the do not. I know your pop off pressure is about 12 psi but maybe you have a check valve that is leaking or something else that is causing the fuel pump side to over pressurize. But you said you had 3 carbs doing the same thing so maybe your testing is faulty.
It’s something faulty. I did have a brand new aftermarket carb I’d rather not use because I have block off the primer nipple and the venturi is a little smaller, but when I test it, it held pressure like a rock. I don’t have a machine cleaner and I’m going to go back at that, make sure they’re 110%
