Merc 650 flywheel play?

[geckogeek]

I just bought a 14' boat with a 1965 merc 650....it runs and all is well but, the flywheel on top seems to have a lot of play in it (up and down). Is this normal? Someone told me it could be, because when it gets hot and expands it will fit snug. What are your thoughts? Could be a bearing or the key is worn?

Thank you very much, JOe

 

[emckelvy]

Re: Merc 650 flywheel play?

The factory spec for max free play on the crank is .012". That being said, your motor isn't exactly new!

If it doesn't make a lot of thrashing noises when running and you don't have a Half Mile of free play, it's probably not going to hurt anything.

The only way to correct that issue would be to tear the powerhead apart and change bearings, end cap shimming, or both.

If it sounds good and runs OK I'd leave sleeping dogs lie!

HTh..........ed

 

[geckogeek]

Re: Merc 650 flywheel play?

ok, thanks....now that you mention it the top end is pretty noisy without the cover.....but what is the worst that can happen...hehehe

 

[Scaaty]

Re: Merc 650 flywheel play?

All motors are noisy without the cover!..listen to what Ed said..he's a master. (PS Ed.."T" will have my 140 rebuild fired maybe Sat..going out there with more painted parts tomorrow..I get the Flatbottom finished and wet, I'll get an album together and put it in Boat Resto...Robby from Oly)

 

[emckelvy]

Re: Merc 650 flywheel play?

I'd be more concerned if you had a lot of side-to-side play in the flywheel rather than up-down.

And if you can hear the Gnashing and Thrashing of the engine's innards from, say, 10 feet away with all the covers in place, well.............:%

How's it sound when you're out in the water; idling in gear, or underway at speed??

If it's not making your ears ring or passengers cringe, maybe it's not so bad.

A compression check would give you an indication of the health of the engine's internals; if you see drastically low readings in a couple of cylinders maybe a problem. But you say it's running OK, so I wouldn't expect it's too messed-up inside.

Robby, better get buzy on that boat, it's supposed to be 70 Friday!!!!! Too bad it's not going to stay that way for a while.

 

[geckogeek]

Re: Merc 650 flywheel play?

There is a significant amount of play up and down....on an angle up right, up left too ( Hard to explain). I would guess 1/8" or more.
I will do a compression test.....maybe it needs a rebuild anyways. I haven't had this boat in the water yet and I'm not really up on my marine mechanics (carpenter by trade). How heavy do you think a merc 650 outboard unit is? I want to take it off regardless to paint the boat.....not sure if I need a cherry picker or not.

Thanks again

 

[Chinewalker]

Re: Merc 650 flywheel play?

I would check the flex-plate. It's the disc that connects the outer flywheel ring with the inner hub... They have been known to crack and loosen up...
- Scott