2.5L 150 Efi Mercury

[Lilwhirlwind1987]

1999 150 EFI
S# 0G803380

Hey guys. I've tried this engine on 2 different boats with the same results. First the engine was on a Nitro 901 Cdx. 21 pitch prop. I could get maybe 50 mph with a load. However that was not on the pad. If I let out of the throttle you could hear it catch grip and the bow would lift and I'd be running 45. Then if I stomped it.. it would fall off pad and just seem like it was in a strain.

Now the engine is on a 2001 Xpress X18 with the same results. This time I'm running a 23 pitch prop. With just me in the boat and no water in live wells it staying on pad and runs maybe 53-54.. if I put a co angler in the boat I get 45 mph. With the same problem as the nitro.
If you ease out of the throttle the bow pops up and runs almost the same speed. Maybe 42-43.
If you mash it WOT the bow drops..
I've tried a new 25 pitch tempest with the same results.

I tried the prop shaft from 3 inches below bad and now after asking around I've lowered it to 5 1/2 inches below.. it seemed to help a little.

Everyone I know with one of these boats are running mid 50s with a load.

P.s. this engine was rebuilt about a year ago. Since then I've probably put around 50 hours on it. I dont think the injectors were sent off to be cleaned either.

Another thing I've noticed is if I let it set a while and especially if I trim It way up, the bulb has to be primed before it will crank.
You can spin and spin it and eventually it will bust off. I guess from the pulse fuel pump priming it.

P.s.s.the compression is good

Any ideas guys.

Thank you in advance

[EuropeanAM]

Has a complete Sync-n-Link procedure been done?

Compression Test, Spark Test, Fuel Quality, Delivery and Pressure (as well as pressure leakdown 15/30/60 seconds) been done?