RPM issues can't get up to full speed

[fatheroftriplets]

Greetings, I have a 2005 5.7 gxi that starts and idle great. You can rev the engine at the dock so it goes up to over 4k (did not want to go farther than that without a load). When you try to get in plane, it is a little slow and tops out at 2700k. Will get on plane but that is about it. I replaced the fuel/water separator filter. I had a friend of mine check the fuel pressure. He said it was 65psi. Sounds high to me. The electric fuel pump was replaced 2 years ago. Any thoughts? (No growth on the props). Thanks in advance.

 

[alldodge]

It takes next to no gas to rev in neutral, takes a lot under load

If the gauge is accurate then pressure is a tad high but only 5 psi. Spec shows GXI C thru G to be 50 to 60 psi. Was it 65 psi when on the water and under load?

If new problem and you have not replaced the distributor cap, do so. The caps can look good and be bad. Most keep a spare in the boat just incase

 

[QBhoy]

Second the Diz cap idea

 

[stouchton]

Any growth on your hull? Since your engine will wind out to 4K no load mechanically (timing, valves and such) should be ok. Simple (but not always correct) cause would be restriction in fuel delivery. Restricted filter, clogged injectors, etc. Keep in mind you will not produce 65psi fuel pressure with a clogged filter under load. Clogged injectors will put a max limit on HP, thus causing the issue.

But, if the bottom is not squeaky clean you will get a similar issue.