Fuel pressure low

[dgie]

Took the boat out today and all was good. With the PCV valve hooked up to the carb there was no oil spewing anywhere. I keep having the same issue with my fuel pressure. I have a fuel pressure guage hooked up to my carb and at WOT I am reading around 3-4 psi I know that is to low, should be around 5-6 psi. I have 2 saddle tanks and they go through an electric selector valve and a fuel/water seperator before it goes to the mechanical fuel pump and then to the carb. I am also running 3/8 fuel line. Any ideas on where my problem could be as a strating point, before I start yanking everything and slowly adding things in to identify where the problem is. I read something earlier that a fuel/ water seperator could limit fuel to your carb, but i think they are a must in a boat, i could be wrong though. I am also not sure about the electric selector valve, bought it at Autozone I think it is for a chevy pickup with duel tanks. It switches from tank to tank no problem I assume everyone with saddle tanks in their boats are running this type of selector valve also.....any thoughts on this dilema? :idea:

[HotDogz]

My mechanical pump could not keep up with the motors fuel needs. At WOT the pressure would drop or sometimes empty the bowls. Went with an electric Holley pump and pressure always stays at 7-9psi. My setup goes from tanks to switch to fuel filter/seperator to pump to carb with pressure gauge.

[dgie]

I originally had a a Holley Red fuel pump, but had the same problem. I switched over to a mechanical fuel pump (stock) and it seems to give me a little more pressure, but I am still loosing it somewhere. Its leaning me out. :squiggle:

[jetheaven.us]

Having burned up my last engine from going lean, there could be a couple of things to check.
1. Tank venting, make sure the fuel tanks are vented properly. It could be creating a vacuum if vented incorectly causing the engine to starve for fuel. (One of my problems)
2. If you are running big carbs, you might think about switching to 1/2 inch fuel line and switch out the electric selector valve for a manual lever. There will be some slowing of the fuel with the electric selector valve if you are using a lot of Carb. (Also one of my problems)
Shane