Mercury 225 EFI rpm problem

[Live2crab]

I have a Trophy 2509 w/merc 225EFI that will not go beyond 2500 RPM @ WOT. That gives us a whopping 11MPH. It runs smooth, compression test good on all cyl (115), spark good/even on all cyl, injectors all flow/pattern test good, detonation sensor replaced, throttle position sensor checks smooth on
VOM, new proper NGK plugs, 35psi on fuel rail. The ECM is advancing timing from 0 to 21 deg. at WOT.
I have a future appt. with a tech to hook diag computer to it at the lake but would appreciate any input

 

[A-37]

Re: Mercury 225 EFI rpm problem

If you have a late model motor with the SmartCraft "Guardian" feature, the problem might be insufficient water pump pressure and/or a bad thermostat on one bank of cylinders. The Guardian feature keeps the rpm down to save the motor.

I had the same symptoms with my 2001 150HP Optimax.