rubber hose from tank to pump... is the pump collapsing the hose?

Good catch, but doubtful. I replaced all rubber line this spring with USCG approved line that is also supposed to be ethanol resistant. Also installed an inline filter before the pump.

My money is on the anti siphon valve if equipped or the fuel pump. Will be interesting to hear the outcome of this. Good luck.

Just take the fuel tank, fuel pick up, anti siphon valve, fuel line, high fuel vacuum (Hg),possible poor quality fuel and the fuel vent out of the mix. I have posted this about 50 times before. Test to see if you have a fuel delivery problem which side or an engine problem.

Buy a 6 gallon portable fuel tank like small outboard boats use, buy a QUALITY fuel line and QUALITY primer bulb like all outboard use, fill it with fresh gas. Unhook your inlet fuel line at the motor side, hook your portable fuel tank and fuel line / primer bulb up. Go to town at the lake.

If the boat / motor runs better to great, you now have found which side of the boat is your problem. If still the same poor running conditions exists, it is not your fuel side of the boat. Also on your portable gas tank do not forget to open the fuel vent completely. When running your engine and problem acts up, squeeze the primer bulb, if the engine clears up or even a bit problem is most likely a fuel delivery problem engine side.

You have to find where your problems are coming from first, drive & prop side, fuel delivery boat side or problem is still motor side. it is that simple to find problems on your boat.

Where is this anti-siphon valve? I looked at my tank pick up and it's just an aluminum tube welded into the tank on my Baja Islander 272.

1st straight pipe to barb fitting on the tank. Looks like a normal pipe to barb, but inside is a check ball with spring.

what are the plugs gapped at?

Gapped at .045.

Only getting 4 PSI with pump running - engine shut off, bypassed the safety switch. Going to look at upgrading the whole fuel supply system over winter. What is a good source for tank pickups? Looking for something with a 1/2" ID. Does it need a sock on the end to filter crud from the tank?

What fuel pressure should I aim for at the carb? Holley 800.

Bud, your tank probably has 2 pickups. You could tie them together. Even if the pickup is to small it should have more pressure with the engine off. Are you sure all your fittings are tight b4 the pump? Also, what kind of gauge are you using to get your reading?