It's random but it really likes to happen when it's time to dock. It usually beeps once and then surge surge surge... stall... and of course it's on the PS engine. I don't seem to have any power restrictions... Both engines spinning out to about 5400/5500. And both run fine even when the surge happens I can just move the throttle up a touch and it runs smooth. The year is 2004. I did change the IAC and then it didn't do it for all my "testing" so I went boating and the second I got near a dock BEEP surge surge surge stall... It does go away eventually but by then everyone is thinking i'm the best boat driver ever... I'm putting all the sensors in my cart now and will get them coming. This is a new boat to me so I need to have them anyways. BUT... if I knew what one to swap out now .... at least I could move the problem over to the non power steering engine.... Thx in advance for anyone will to help.

I would have guessed IAC first based on what you describe. Next guess would be the TPS. Need to put a scanner on it and check for codes.

Yup, codes. How do the ign Dist cap and Rotor look? Fuel pressure holding good. It knows why it is beeping, see what the codes are before throwing parts at it.

the 525 doesn't have a conventional distributor it is coil on plug and it is crank fired off the reluctor wheel on the balancer

Similar EFI engine in my post below for reference on what to check. BTW I still haven't solved it!

Help Chasing Erratic Idle Please