Flywheel stuck

1980 evinrude 9.9 hp

The flywheel is stuck and will not come off the shaft. It has been slipping off and the key falling out recently. Yesterday it can off at wot and now I can't get the flywheel off. I've bent several sets if bolts on my flywheel puller as I tried to remove it. It appears the flywheel is up about 1/8 inch and that happened when the key broke. I've tried heat, two types of wheel pullers, and also tried to hammer it back down flush.

It spins freely so whatever is wrong is between the shaft and the flywheel.

Any suggestions? I'm almost to a point where I want to cut it off somehow.

Thanks in advance!

Don't know if this will help. There's alot smarter guys on here than me.
Get alot of pressure on the puller, firmly tap the center piece that sits on the crank, more pressure and tap again, more pressure and tap again.
I did this with a balancer on a 427 Chevy. When the sucker finally let loose, it literally flew off the crank.
By what your talking about, the flywheel may have shifted and the broken keyway is biting into it.

overboard said:

Don't know if this will help. There's alot smarter guys on here than me.
Get alot of pressure on the puller, firmly tap the center piece that sits on the crank, more pressure and tap again, more pressure and tap again.
I did this with a balancer on a 427 Chevy. When the sucker finally let loose, it literally flew off the crank.
By what your talking about, the flywheel may have shifted and the broken keyway is biting into it.

Click to expand...

+1

Thanks guys. Great tip. That thing popped right off. Now I gotta see if I can get this flywheel balanced or if I need to buy another one.

Show us some pictures of the crankshaft.

Here is a pic of the chipped spots. The first time it happened I was on the water and didn't realize it chipped. I just thought the puller I was using pulled off. The second time happened at home. I didn't have the right puller at the time.



Edit: sorry the pic is upside down.

Looks like your going to need to clean up the crankshaft a little. Carefully remove all the burrs and high spots with a file then clean up with some 400 to 600 grit sand paper. Do the same for the flywheel. Use some acetone or carb cleaner to remove all traces of oils from both surfaces.

Ok I'll do that this week. Do you think that has something to do with the flywheel jumping off? I am a little concerned about the 4 chunks I chipped off too.

This motor used to start and run well, but had always had the issue with the flywheel coming loose while in use. Lately it won't am ways start when I first hit the lake but fires up after I am on the water an hour or two. It fires right up on the water hose though.

If that's 3 chunks missing in that one picture, it may cause balance/vibration issues since they are all on one side. Looking at a blown up image of the crank it looks like the threads are squished. Did you smack the end of the crank with a hammer and the nut wasn't on the shaft?

The first part of the thread is slightly deformed, but not as bad as the pictures makes it appear. This was done by another owner.

There are actually four chunks taken out on one side.

I agree it could create a vibration that may lead to other issues.

Can a machinest "balance" this by removing materal with a drill bit on the opposite side? Or should I hunt down another flywheel? A new one is really expensive, but used ones seem to run on around $50 or so.

I like this little motor, but it has become rather unreliable lately. Part is due to the flywheel coming loose every trip lately, with the last one causing it to get stuck. It also is having fuel issues which I suspect is ethonal related. I treat my gas, but that junk still causes issues.

If it we me, I think I'd start it up and check for any vibes. If you think it's causing excessive vibrations, I'd buy the used one to replace it. You say your flywheel keeps coming off. Does the nut keep backing off? If the nut keeps coming loose, I'd put some locktite thread lock on it.

Unsure if nut is getting loose or what...not sure what else would cause it to come loose though. I'm thinking maybe a vibration is making the but back off just enough to make the flywheel come off. The key falls out when this happens but is never damaged and is tight when I reinstall it.

I think I'll hunt a good used flywheel and a tube of lock tight and see what happens.

Are you using a Torque wrench when you tighten down the factory nut to the correct specs, if not it will continue to come loose. Make sure you check the crankshaft key way for any damage from the flywheel coming off, use a factory OMC key and not some hardware store woodruff key. Good luck, those are great motors! P.S, If Torqued properly using the correct parts you won`t need ( or want ) any loctite on there.

I don't have a torque wrench nor do I know the correct torque amount.

Ill buy a cheap torque wrench and look up the torque setting. I need to figure out how to keep the flywheel from moving whole I torque it down. That's probably part of my problem.

I have a new key from the local auto parts. Ill order a couple new ones from OMC.

I dropped the flywheel off with a buddy today. His buddy is a machinist. He's going to try to balance it and clean off the burrs on the inside. If that doesn't work Ill find a good used one.

Thanks everyone for the help. I learn something every time I log on.