I did have a sea water pump leak on that motor last year its replaced now but it did drip for a few weeks.The Iac is new I had one but it idles fine.Is the crank sensor held on by a 7mm bolt like GM? At least I think thats what size it is its been a while since I changed one.
Thanks

Ok today
Took one baffles out of each port exhaust tips so the match starboard
Changed crank sensor
switched from port to starboard
water pressure switch
coil
map sensor
TPS
changed fuel filters
inspected cap and rotor little corrosion but not bad, cleaned

Still same problem I ran it WOT and let the alarm scream to see if it would get hot or loose oil pressure.It didn't Starboard motor will wind but port only goes to 3500 3600 and the alarm while mostly constant does go in and out.The tach flutters a little so it appears that I am loosing ignition or power to the ignition.I have a lot of water coming out of the exhaust and the impellers are new.Will run a fuel pressure check tomorrow but doubt thats it.I am about to condem the harness and it was changed last year.Thoughts????

Ignition wires?? can't see why that would throw an alarm I am guessing at this point.

Has it run good with no alarms after your new exhaust?

I you suggest leak down and compression test. Also a plug check and make sure the firing order is correct.

No but I did not run it this year with the old exhaust and the other motor is fine so I don't think its the exhaust.I checked the firing order three times its right.I did a fuel pressure check good motor was 55-60 other was 35.Changed regulator and it went up to 50.Ran it on a mercury box that replaces the boat wiring harness no alarm (because the alarm was bypassed) but still would not wind and got a little hot there were no numbers on the box gauge so I don't know how hot.I can use a Mercury computer tomorrow morning so see what happens.I have not done a compression or leakdown test yet but its the next thing after the computer.Starting to wonder if I hurt a motor but it runs and sounds great till 3500.Did a cylinder drop test by removing wires off the cap and got an RPM drop each time.Don't know but I am running out of things to check.Impeller is new but I could be loosing water pressure at high RPM but running stopped at 3k it seems to be the same coming out of the exhaust as the other motor.

try cleaning the grounds on that engine giving you trouble,,,

Fixed winded up being a shift selector switch I had it on a mercury computer this morning and it was going into guardian.Why it did not show up when I had someone else scan it I don't know but the ECM thought the port motor was in neutral and would throw it into guardian over 3500 if you held the throttle there.

Thanks to Southwicks Marina in Beach Haven NJ for all there help this weekend.The have 93 octane so if you need fuel stop by.

Good deal Tim, glad you got it all squared away and it wasn't a big deal to fix!!

Like I said on the phone, sorry I didn't suggest that, I just didn't think of it!

No problem every thing is easy once you find it.I can't believe I did not think of it either.Like the other thread with the 500s cutting out one guy said check the kill switches never would have thought of that.Thats one of the reasons we do theses threads is for the next guy