mercruiser rpm jump to wot bat no go help

[bolo78910]

it seem today is a bad day before fathers day, my friend just call stating he was heading to the reef doing about 3000 rpm when the rpm and the shifter just jump to wot, boat no go as if it is in nutral.

engine 1989 merc 5.7 260 alpha one drive he did have to get towed in . , when engine start runs fine try to put it in drive no thud no gear ingauge nothing just rev, mechanic said it could be the coupler .

i said it might be the shift cable came of inside the bell area because i dont think the coupler should stop the drive from get in forward or reverse gear, but who am i i dont know shuz i am having a prob of my own and looking fro help also.

your thought guys

 

[Don S]

Re: mercruiser rpm jump to wot bat no go help

That is one of those problems where just looking at it and seeing what moves when and how far is going to tell the story. 100 different people could guess 100 different possible problems. Time to go looking. But I doubt it's the coupler. No mention of overheat, loose the coupler and you loose the raw water pump in the drive. Besides, the coupler doesn't change direction. It always turns the same direction and speed as the engine.

 

[bolo78910]

Re: mercruiser rpm jump to wot bat no go help

thanks don i foget to let yall know that it is a close cooling system that pull its seawater from a belt driven water pum through hull pick up.

like i said engine start fine runs fine shift from n to d do nothing to r do nothing no sound of gear inguage, the cable on the brackec move but nothing happen.

 

[Bondo]

Re: mercruiser rpm jump to wot bat no go help

Ayuh,.....

By your description,...
It's either the Coupler has Spun, or the Prop Hub has Spun....
Probably the Coupler....

Bad motor Alignment is the usual Cause....

 

[Don S]

Re: mercruiser rpm jump to wot bat no go help

when engine start runs fine try to put it in drive no thud no gear ingauge nothing just rev,

Geez, when I read the above, I took it that rev (reverse) worked, you meant the rpms went up.

 

[bolo78910]

Re: mercruiser rpm jump to wot bat no go help

lol yes don i meant the rpm went up

 

[bolo78910]

Re: mercruiser rpm jump to wot bat no go help

update the mechanic pull the drive and he claim the coupler is good, the problem is in the upper gear, said the gears are damage and there r little or no oil up there.
so iam thinking maybe the last guy who work on the drive a few weeks back maybe fogot to put oil in the drive.

well who knows .