Yet another CARB pressure question?

[Shane0524]

I just rebuilt my carbs and put them on the boat,,, it didn't run right and was flooding when stopped. So i pulled the carbs and found one of the hinge rods from the needle arm was not in its slot correctly and was causing a low pop-off and some leakage. I also decided to do a pressure test with about 20 psi, the pto carb holds fine but the fuel pump mag carb has a hissing noise and it leaks out of the back hose hole on the fuel pump. when i cover that with a finger its quieter but it still hisses from somewhere. is this a problem or is this normal

 

[Sportster-2001-951C-Stock]

That nipple you're blocking off should the fuel return that leads back to the tank, you need to be blocking it off for the pop test. Mostly, both carbs each have a fuel return that "T"'s together before leading back to the fuel tank. If you're pressurizing both carbs simultaneously both returns should bleed off pressure until you block the returns I think?

But, you need to test each carb pop pressure separately.....

Otherwise, if there's a leak somewhere before pop occurs that does sound like an issue. Sometimes a piece of hose in your ear can help isolate the location of hissing, clanking and banging.

 

[Shane0524]

I replaced the clear check valve diskS in the fuel pump and now it doesn't make a hissing and is popping nicely.