Originally Posted by JimN
Check the fuel pickup in the tank and the anti-siphon attached to the aluminum block on the top of that. If it doesn't have an anti-siphon, make sure the fuel shut-off is fully open.
Stop replacing parts unless you can prove they're bad. I seriously doubt the MAP, TPS or IAC were faulty and the whole reason these engines have trouble codes is so time, effort and money isn't wasted on replacing parts.
The rev limiter kicks in at about 5200 RPM. The IC module isn't at fault- you already measured low fuel pressure and you need to keep going in that direction, IMO.
Great info! RPM limit 5200, boat does not get even close to this, 4500 max rpm from 3/4 throttle to WOT.
I will check the anti-syphon / fuel shut off is all good. Fuel pump module was removed, cleaned and new filter installed. Loads of muck in fuel pump inlet screen, fuel system now clean and performance has improved.
I also read in the manual that the fuel pressure is meant to be 25psi, although I have measured this at ignition, idle, and up to 2000 rpm and it holds 25 psi.
Because of the inherrant risk of holding a fuel pressure guage on the motor at full throttle on open water I have not done so but will be installing a fixed guage (and then removing it) for a test. The PO I believe turned the screw on the bottom of the pressure regulator out by 3 turns (because of a previous over fueling issue) so I might screw this back in as well.
The list of parts was either checked / repaired or replaced. ( not all replaced) This was meant to give a little history so those more experienced than me can see what has been done so far and provide me with addidtional valuable info... Which is excatly what you have done. Thanks!!!