803 not generating

[funky winkerbean]

My 803 has only 36 hrs on it and today while running with power out it started running weird and not generating. The engine was running (badly) and the generator barely turning. I shut it off and when I crank it only the generator turns. What came disconnected between engine and generator? Thanks. Jim.

 

[bobs461]

Sounds like the front half of your crankshaft snapped. The rear half is spinning the generator through the starter/ring gear...Ouch!

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[funky winkerbean]

Sounds like the front half of your crankshaft snapped. The rear half is spinning the generator through the starter/ring gear...Ouch!

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What about whatever bolts secure flywheel to crank?

 

[bobs461]

What about whatever bolts secure flywheel to crank?

Yes, that's true. If the flywheel bolts got sheared off (or fell out), the flywheel will spin the generator, and the engine won't spin. Hopefully, that's your only issue

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[bobs461]

Pull the starter and see if you can diagnose the problem. Keep us posted

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[funky winkerbean]

Pull the starter and see if you can diagnose the problem. Keep us posted

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Will do. Thanks

 

[Light in the Dark]

Let us know what you find.

 

[Bluevic443]

The 5 bolts that have the white stripe are the ones that hold the flywheel to the crank. Have other pic of the area if needed.

 

[funky winkerbean]

The 5 bolts that have the white stripe are the ones that hold the flywheel to the crank. Have other pic of the area if needed.
View attachment 808524

Ok thanks. Either they sheared off or loosened and came pit I’m thinking

 

[Ray70]

Unfortunately you have to tear down the entire generator to get in there. It's not the greatest of designs.
You are usually better off just removing the radiator support and pulling the motor/gen out as a unit then tear the generator head apart to get to those bolts.

 

[fosgittr]

Unfortunately, those bolts shearing off is usually the result of something else bad happening. I have seen both an 802 and and 803 now where a connecting rod end came off and caused the engine to seize, resulting in those bolts shearing off due to the massive force from the sudden stop. You may want to take a socket wrench and see if you can turn the engine using the main pulley bolt. If you feel solid resistance, there is something wrong in your crankcase.

 

[Light in the Dark]

Yeah thats a whole lot of mass to suddenly not want to turn.

 

[funky winkerbean]

Well- I finally got some time to tear it apart and found all 5 flywheel bolts sheared off. The engine was still running so the crankshaft wore the flywheel alignment step so it won’t center perfectly on crank. Gonna need a new flywheel. Anyone know where I might find one?

 

[Ray70]

A new flywheel isn't gonna be cheap unless you can find someone parting out a machine.
Here's a new one but it's almost $300... which is still better than the $1000 GM Generators wants!

ONAN 186-6467 - FLYWHEEL ASSEMBLY ONAN/CUMMINS - Original OEM part

Discover the best deals on 186-6467 FLYWHEEL ASSEMBLY /CUMMINS from Cummins. Experience top-notch quality, unbeatable prices, and fast shipping.

www.smallenginesprodealer.com

There are others available, but more expensive.
Just google 186-6467 and a handful will come up.

 

[funky winkerbean]

ok thanks. That’s a different number then the one stamped in the flywheel itself?

 

[Chainbreaker]

But...what caused all 5 flywheel bolts to shear? Have you pulled the oil pan off yet to examine the lower end of engine? It might take some additional parts beyond just the flywheel. Might want to hold off on ordering a flywheel until you know status of engine.

You did mention that your engine was running badly after you lost AC out of generator. Wondering if you were running on 3 cylinders...?

 

[funky winkerbean]

Yes it was running but poorly. I was assuming with the flywheel not turning it had no balance or counterweight to keep it smooth. Although something else could be going on? And I am concerned about WHY the bolts broke. We’re they never torqued properly? Or did something else in engine cause that. Although I work on diesel trucks for a living and never seen flywheel bolts break regardless of the catastrophic event that took place.

 

[Guyfang]

ok thanks. That’s a different number then the one stamped in the flywheel itself?

There were about three different suppliers for the flywheel I know of. what part number do you have on the flywheel?

 

[funky winkerbean]

170-4287. I didn’t see any pictures on the ones that I looked up with that other part #. Just wanted to make sure I was ordering the right one.

 

[funky winkerbean]

170-4287. I didn’t see any pictures on the ones that I looked up with that other part #. Just wanted to make sure I was ordering the right one.

That’s the # stamped in casting. The printed # is 30554-88-20234 MFR 44940