Stuck flywheel :(

[kicked by a horse 22]

Alright folks,

I am in need of some serious help. I have a 1978 D-160 with a onan on it.

It had been running all summer with no complaints, a pretty regular worker for moving , tilling, plowing etc.  This winter I fixed up a snowblower I found, put it on, and thought I was all set for winter. After our first snow of the season, I went out to get busy and couldn't get it started. It would reluctantly crank but did not want to turn over.  I did replace the battery and was eventually able to get it started.  I got about six feet out of my shed, engaged the snowblower, and then it died and would not restart.  Since then I have replaced the starter, and in the process noticed the flywheel would not turn. I pulled the plugs and removed the blower belt, and still no movement. In prep for winter I replaced the oil and filter. I just checked the oil level and it was over the full line, but I have not run it more then 15 minutes since changing it.  I also winched the tractor about two lengths (it rolled) to get it back in the shed. I don't recall now if  I disconnected the hydro (so I could make room to get to the starter) before or after I winched it, not sure if it matters.  Any thoughts for what could have happened to cause my previously reliable worker to now be a no go? What are my next steps from here. The motor is still on the tractor, hydro disconnected.

Many thanks for any thoughts you can offer.

[TT-(Moderator) 1,162]

I believe I would use a pry bar inserted between two flywheel cooling fins to GENTLY attempt to turn the engine in the OPPOSITE direction of normal rotation. (the engine spins clockwise at the flywheel, so turn it CCW)

 

Being it's a hydro D series, you might want to disconnect the pump drive shaft and try turning the engine. If the engine turns, the pump is locked up.

 

If the engine still does not budge using the pry bar method, it might be time to remove it from the tractor and - at the very least - remove the flywheel.

 

Will await an update.

[Desko 624]

I had a onan p216 do the same thing on a generator turned out that the magnets came off the flywheel and jamed into the stator

Edited January 4, 2014 by Desko

[kicked by a horse 22]

Thanks for help.

The hydro shaft is disconnected and it spins freely.  I tried to spin with the fins as hard as I was comfortable doing clock wise and counter clock and it did not budge. 

[TT-(Moderator) 1,162]

I can't offer much more help beyond the engine & flywheel removal.

Once that's done, you'll have a better idea of what to do next.

 

Edited to add:

On second though - make sure it's not something in the PTO at the "front" of the engine

I don't know if that's possible, but I would thoroughly check all of the externals first.

[Desko 624]

Take the oil filter off your motor is pressure locked and then turn it over

[Desko 624]

Oh and don't start it just turn it over by hand to see if will crank or try the old filter and see if it runs

Edited January 4, 2014 by Desko

[JackC 617]

Here is where you can get the service manual if you do not already have it.

 

There is a section for flywheel removal.

 

http://www.cumminsonan.com/www/pdf/manuals/965-0250.pdf