60 hp mariner low rpm's at wot

[mrivela]

Ok took the boat out yesterday was running good all so ran good all last summer with no problems i have had it out like 6 times this year with no problems well yesterday while crusing at wot it all off a sudden lost half it's power and would not go back up to rpm...

when it's in neutral i can rev it up and it takes right off i can rev the rpm's right out but soon as i put it in gear and take off put it to wot it only goes like half the rpm's it should.

I have checked spark i have good spark in all 3 cyclinders it's not starving for fuel like i said when it's in neatrual it takes the gas fine and will winde right up like there isint a problem at all so i'm confused how could it rev up so good in netrual but when in gear not plenty off spark plent of fuel what could be the ishue any ideas? i was told it could be the stator.

 

[kartman]

Re: 60 hp mariner low rpm's at wot

thats what my 80hp was doing, and it turned out to be a bad cylinder. do a compression check. if thats good, tune the carbs. while your at it, i recomend changing the impellor. its cheep insurance.

 

[mrivela]

Re: 60 hp mariner low rpm's at wot

when you mean bad cylinder do you mean that the cylinder walls is cracked or something or do you mean it's just not firing.

 

[mrivela]

Re: 60 hp mariner low rpm's at wot

ok well figured out the problem....... never going to beleave this! just took the boat out for a ride and sure enough when i first got out there i t ran great full rpm everything...
then all of a sudden it did it again went to half rpm so i pulled the plugs and when i looked at the plug on the top cylinder it had piecses of the piston head stuck to it fowiling the plug so i put a diffreant plug in and it ran fine again uintil fowoling again..
so for some reason the piston head is breacking into small lit piecies and fowiling the plug i'm assuming my motor is junk right?