Mine went to around 2800 (MEFI1 before repower) when it sensed a knock, it just retards the timing and won't let it advance

I believe this may be my problem!!!! Here what I found from the manual. I may have lost oil pressure and the engine when into power reduction mode. I cant explain it not starting back up but in my driveway it idled for 30 to 40 minutes and sounds fine. When I advance the throttle to 1800 I can here it missing in a cylinder. My tach is off I know that so what I perceive to be 1800 could actually be 2800. HOW do I remove power reduction mode? Ill scan the computer tonight with my voltmeter and see if I can clear the codes.

DISCRETE SWITCH INPUTS - POWER REDUCTION MODE (1996 AND OLDER MODELS)
Several discrete switch inputs are utilized by the system to identify abnormal conditions that may affect engine operation. Pull-down switches are used in conjunction with the ECM to detect critical conditions to engine operation.
If a switch changes state from its normal at rest position, that is normally open to closed, the ECM senses a change in voltage and responds by entering power reduction mode.
This engine protection feature allows the operator full engine power up to 2800 RPM, but disables half of the fuel injectors above 2800 RPM until the engine RPM drops to 1200 RPMS.
This feature allows the operator a comfortable maneuvering speed while removing the possibility of high RPM engine operation until the problem is corrected.
Switches which are used with the Fuel Injection system to detect critical engine operation parameters are:
Switch Normal State Oil Pressure N/O I/O Fluid Level on Stern Drive N/O Transmission Temperature on MIE Models N/O Engine Coolant Temperature N/O

PRM is not going to kill the engine and then not let it turn over. Low oil pressure may cut off the fuel pump and in turn kill the engine, but the engine will still crank. If you're hearing a knock, then you've probably got something unhappy inside the engine. Can you take some video and post it up for us to listen to?

If you can, get video of the engine starting and some light revs so we can hear it what's going on. Get as close to it as you can.

For spark knock it will retard timing until the knock goes away OR it reaches max retard, which is typically around 9 degrees less than programed advance. Advance will return when knock is eliminated but it slowly feeds the advance back in. The rate of knock retard, max retard and rate of feed back in are all set in scalars and constants.

I will post video but seems like the problem went away. I put 89 with ethanol in the boat that day so maybe I got some bad gas and i hearing a spark knock. Going to the lake tomorrow. After I tested all three sensors....oil pressure switch, outdrive oil, and ect I heard the engine clear up at idle. Did a couple revs and sounded ok. I'll post what happens.

Bad gas will keep it from cranking?

No.

Ok looks like I also have a starter problem. Has been starting fine in the driveway but soon as I get to lake click click click. I tapped the starter wire and went for it . Noticeably she felt like its running on 4 cylinders. Hardly enough power to get on plane. Shortly after planing she starts to die BUT she starts right back up and idles fine. Drove out a whole quarter tank of gas just putting around 1500 rpm. No knocks sounds fine. Soon as I get on it back to the same old thing. I can idle all day and it sounds fine but lost power. I can't tell if the sound is a dead cylinder or something major but when I try full throttle it sounds like a cylinder or two it's missing fuel. When on plane and the engine dies it DOES start back up. No codes again.

https://youtu.be/f128CFiOI3c

https://youtu.be/F4usVo3M0vM

Have you checked fuel pressure?

So now the engine is not knocking? My head hurts from all of this. :bong:

You need to check fuel pressure under load (while driving, not on the hose).