Originally Posted by Mikeyb
Fuel pump installed. Limited pressure to 30 psi but I have an AFP FI fuel pump. I found a leak in the pump!
Leak testing is an art. It’s hard to define an acceptable leak rate. You are looking for bubbles that take 10 minutes to form 2mm diameter in pure water. Using a real leak detection fluid like “Snoop” helps because it forms small bubbles faster that look like fuzz. It’s not hard to get it tight enough that the pressure remains unchanged for days and you can see the pressure rise and fall with temperature.
This is not the only pump that has leaked. I used 30 psi and have been promoting this test method for 5 yrs or so. It is really the best way to find the leaks. Pick your best detector fluid!
To the OP question about leak down overnight. It should be really small like a couple psi, if 10psi then you likely still have a leak. Always be sure to bench test the fuel pump assembly as much as practical . . . the fewer joints to test in situ is just a time saver.
Be sure to torque your 3003 tubing B-nuts not just tighten them, they can be over torqued, damage the flare, and result in a possible failure point in the future.