2011 90 Merc 4-stroke

[1Moon]

I just got a pontoon with a 2011 90 Merc 4 stroke and it's acting up. It runs great until I try a full throttle pass. In about a 1/4 mile or so it beeps then goes into limp mode. The impeller seems to be pushing a good stream. The prop seems a little loose. Any of you gurus got any ideas to check? This board helped me rebuild my old 2.5 so I knew where to go with this question.

FYI..I've put about 1 hour on the motor so it's new to me.

[racervboat]

Is the oil level full? limp mode is over heat or low or no oil pressure.

[King Dad]

The engine goes into "limp mode" and then.... what do you do? Shut it down? Re-starts? What rpm is "limp mode" on your tach? If you do a 3/4 run, all day, it runs ....ok?? If you go WOT and into "limp"... it stays in "limp" even if you reduce throttle slightly? "Guardian Mode" reduces rpms all the way down to about.. say.. 2500 rpms and won't allow you to go back up unless the problems don't exist anymore and in most case, you have to stop the engine and re-key the ignition. So, it's not hitting the rev limiter?? ie: horn beeps at max rpm say, 5500 and engine stumbles but if you drop to 5100, it runs ok? If so, then I'd say, wrong prop, motor mounted too high or trimming out too far.. Most pontoon boats don't give you much trim like a "normal" boat so it's ez to ventilate the prop and over-rev.. IF, that's whats happening.

[1Moon]

Thanks for the replies. Yes the oil is full. King Dad- After the horn beeps I pull back the throttle and I let it idle a few seconds then it works fine. I've only had to cycle the key once after the beep.

This morning I made a few WOT passes the tach pegged out at 6100. Ran perfect for a half mile. I pulled back on the throttle, about 1/4 throttle, to turn around then hit it again. It got to about 4000 then beeped. So IDK, I pulled it out of the water and the prop seems loose so I'll put on another that I have to see if that helps.

Does anybody know what the rev limiter is set at?