657 engine crankshaft turns hard help

[sirgmfk]

I did open the magneto case and pulled the flywheel out. I found that actually flywheel rubbing surface on the back of the housing. How is that possible? Is that might be a crankshaft seal misaligned or flywheel bad? Maybe anybody had the same problem before?

 

[AKnarrowback]

This is not a normal problem, I've never seen rubbing in that area before. The parts of the motor that are involved in maintaining the clearance on the flywheel are pretty stout so rubbing is not a good sign.

Was this a sudden problem? What alerted you that something might be wrong and led you to look into the motor? Was the flywheel pulled off recently and put back on before this problem appeared? Give us some more background info.

It looks like the ring gear may have shifted. Look on the other side of the flywheel and see if the gear is seated snug against the flywheel ridge all the way around. The key, magnets and stator look to be in good shape which makes me think the flywheel itself is still true on the crank. I have never seen a ring gear shift, but the ring gear and flywheel are two seperate pieces held together by friction so it is possible in theory.

 

[sirgmfk]

The original problem was that the engine won’t start. First I replaced the starter and it didn’t fix the problem. Then i was thinking that the impeller bearing stuck and pull the pump off. The engine still won’t starts just clicks. There was nothing wrong with pump.Then pull the whole engine out and start open the top thinking the piston locked up with something or rotary valve surface scrued up but do not see anything wrong. Then open mag side and pull the flywheel and found that. After pull the flywheel out crankshaft spinning like a baby with two fingers. Has never pulled the flywheel before and put it back. One of the idea was that the bad crankshaft seal and thats why start to open the motor to get to the crankshaft seals. I really dont want to open the bottom if its not the seals problem.

 

[AKnarrowback]

Unless you see signs of fuel/oil liquid sitting in the bottom of the flywheel compartment I wouldn't go any further into the motor yet.

Did you check to see if the ring gear shifted?

 

[sirgmfk]

Yes you was wright. The ring gear shifted about an quarter of inch forward. Is it ok to press it down back or better get a new flywheel assembly? If I press it down back do I need to timing anything or it don’t matter?

 

[AKnarrowback]

No, no timing required. Unless you can see some obvious damage that causd the gear to fail you should be able to re-use everything. Press it back on but pay attention to how much force it takes to move it. It should be tight, if it moves pretty easy at any point then something is not right and you need to look further into it.

WHY it shifted forward is the big question. Like I said, I have never see a ring gear shift on the flywheel. It is pressed onto the flywheel. Does the ring gear have any sign of a crack or damage that would cause it to be loose?

 

[sirgmfk]

I did press the ring back using 2x4 and hammer. I do not see any cracks etc, but I’ve noticed that the teeth chewed by the starter. Are they still ok to crank or it’s bad bad and will make me a problems in the future?

 

[AKnarrowback]

The teeth don't look bad, run as is.

Make sure the ring gear is fully seated on the flywheel. Make very sure the crank taper and taper in the flywheel are dirt, rust free and the flywheel key is solid in place and put things back together. Spin it all by hand and if everything goes smooth give it a hit on the starter and see how things go.

If it looks good to run then go ride, but I would look into that flywheel compartment pretty often to see if that gear is walking off again.

Good luck and let us know how it goes.

 

[Lake Sailor]

Shop manual for '97 Doos says to install ring gear with Loctite 648 retaining compound. Wonder if a PO failed to do so?

Might wanna take another whack at it...