3.5 psi  is a good pressure for carbs. Have you done a fuel volume test. Pressure and volume are not the same thing. You can have one without the other.

On 6/26/2020 at 2:54 AM, jonbill said:

3.5 psi is a good pressure, but if you loose pressure with the return line open, maybe the pump isn't moving enough fuel. can you install that pressure gauge so you can see it when you drive? it would be informative to know what happens with the pressure when you have that lean condition.

if thats a pain, I'd be inclined to try adding a cheap inline electric pump. you've probably got wires for one down at the fuel tank sender.

 

 

 

 

I may just go the electric route with a fpr I have another mechanical pump I'll most likely swap to to see if that makes a difference but the sure bet is an electric if the mech. pump can't keep the supply up.

On 6/26/2020 at 10:22 AM, Mark Maras said:

 3.5 psi  is a good pressure for carbs. Have you done a fuel volume test. Pressure and volume are not the same thing. You can have one without the other.

I have not. I feel it could be the volume as the triples need volume but not pressure as you said. 

I did a couple tests wide open and no throttle at all. Numbers were roughly 110, 90, 110, 120, 120 and 130.
We compressed some air into the cylinders and the bottom end seems solid still. I'm guessing valve issues still. 
And oddly enough the driver side seemed slack and the passenger was tight. My car is lhd

I thought you had to have throttle wide open on a hot engine for an accurate compressions test? It needs to breath between pressure readings right?

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