96 J150 griding gears past idle?

[lamphax]

Hello,

I was planed out at half throttle when the engine revved out really high making a grinding noise. I shut it down and made visual inspection; saw nothing wrong. Fired it up and engine runs great but... If I get it over 1200 RPM's there is a terrible grinding noise and the prop stops turning. Its like a bad clutch in a car - can milk it along but slips badly with torque applied. I guess I am hoping this is a common failure that can be fixed without rebuild? Anyone have a recommendation?

 

[Daviet]

Re: 96 J150 griding gears past idle?

Check your lower unit oil for any metal particles.
Check and see if you spun your prop hub.

 

[Dhadley]

Re: 96 J150 griding gears past idle?

Have you tried your spare prop yet? Might just be a spun hub but they don't normally make a grinding noise.

 

[lamphax]

Re: 96 J150 griding gears past idle?

Thanks a bunch, both of you. I will check the oil tonight ... how do I check for a spun prop hub?

 

[Dhadley]

Re: 96 J150 griding gears past idle?

Just look at the hub, if it's burned looking it's probably spun. I'd normally say to mark it and try it again and if the maks don't line up it's spun but I'm a bit concerned about the noise. If the oil is OK then just put the spare prop on and try that.

Has this prop been on all the time? Or was it just off and then back on for some reason?

 

[lamphax]

Re: 96 J150 griding gears past idle?

Have not had the prop off before. We don't have a spare prop so will go out and get one ASAP. The noise certainly scares me too. I found a local guy who has a used lower unit for sale for $300. I guess if the prop doesn't fix it I can try that. Otherwise, if I need a new lower unit, is it cheaper/better to have the shop rebuild mine or get an exchange?

Thanks,

Don

 

[lamphax]

Re: 96 J150 griding gears past idle?

BTW, the lower unit oil looks brand new and no metal chunks or any other alarming indicators. By researching more I am wondering about the coupler. Is it possible that the grinding noise could be explained if the coupler was bad? The noise sounds like a transmission with worn synchro gears and only happens under load. Also, we idled in to launch for 15 miles without any overheating or any other issues.

 

[lamphax]

Re: 96 J150 griding gears past idle?

Dhadley/Daviet,

Thank you very much for the help. It looks like it is a spun prop hub. I took it down to Nettles Prop in Austin, great people down there too!

Have a great week!