Thank you for your reply and your help. It is very much appreciated. I wish you were closer cuz I would bring it to you in a heart beat. I also wish there was somewhere around me that worked on many 496s

if it was mine i would replace the ignition switch and the kill switch,i have seen ignition switches do weird things.many years ago i had a jet boat that i parked in a buddy,s garage,he called me and said the boat started by itself in the locked garage ,he pulled the coil wire and called me about it.i thought he was kidding but he was not.it ended up being the ignition key switch.

I put a new ignition switch in it already with no fix. Thank you for your reply though. I will check in to kill switch though. Thank you

My first thought is the power relay. You also could jump the ignition at the engine to rule out ignition or kill switch as a source.

But he has reported turn key for a fast start before horn output and the engine will run fine ALL DAY LONG is this correct for what I am saying.

A scan the MPR = main power relay should show up as fault or varying voltage. IMO someone with scanning indepth experience might be able to catch something.

he did mention changing the ign switch already in a past post.

IMO I think the horn output / PCM side is the problem.

BUP on the horn output/ pcm are you referring to the pcm itself or the wiring on that side or both. Also on the relays I have like three or four on top of the pcm and then there is one single one behind dash near ignition switch. Anybody know if that the mpr or if it's somthing different. I was under the impression that the mpr was on top of the engine

horn output / warning horn the PCM has a internal horn driver. As I asked from your statement saying this is the case with your engine - I am reasking again ----- if you quick start the engine before the one beep at the dash goes off you can run this boat all day long without any problems and NO WARNING HORN going off is this correct ??

If you start the engine after you here the one beep from the dash ---- so describe what happens with the engine running for X amount of time and then do you get a warning horn going off ???

KEY ON ONLY ONE BEEP IS NORMAL FYI but after starting the engine and running what happens ? asking again to be clear here.

Has anyone ever hooked up the battery wrong ? I am suspect about this one 3 sure

Yes that is correct if I quick start the boat with no key on beep the boat will run fine.

If I start the boat after it HAS done the key on one beep, after a few seconds of idle it will almost die and then rev up real quick and all gauges will cycle and single beep just as if you turned the key of and then back on real fast.

To my knowledge the batteries have never been hooked up backwards

Also once it does that it is very irrational and continues to do so at random times while idling around and running wot down the lake.

Had a similar issue on the 496 HO.. After a year of the mechanic throwing parts at it, IAC, fuel pressure regulator, relays, fuel pump, filters, grounds, ect. Finally it completely turned into a no start condition.

End result that fixed the issue was a very expensive $2K PCM. Video form my thread happens around the 20 sec mark

https://www.youtube.com/watch?v=YjpOWyRCmk0 http://www.offshoreonly.com/forums/g...off-video.html