17hp twin cylinder FH500V, play in the crankshaft

cdestuck

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I'm working on a LX277 with a twin cylinder FH500V, 17 hp air cooled. It did not have a starter. I bought a starter and installed it and noticed the flywheel teeth were resting on the starter teeth, they couldn't disengage. This is a side mount starter, not a top mount so the there was no way that it was just a spacing issue, the bolt pattern for the starter was fixed. I started the engine and it ran nice and smooth, no smoke at all. The starter could not disengage so it grinded like all heck so I had to stop the engine after only 3 or 4 seconds. The flywheel rests on the cone shaped top of the crankshaft so there was no spacing that either. I notice some up and down play in the crankshaft, A LOT of up and down play. I could raise the crankshaft a full 5mm (about 1/4"). With the crankshaft raised the flywheel easily cleared the teeth of the starter.

Obviously I am thinking the worst. How else could the crankshaft have dropped that much unless it has worn down into the bottom bearing of the short block? There was no metal in the oil when I changed it. The engine turns over and spins very smoothly. Very good compression. No oil leaks at all, not from the top or bottom oil seals or anywhere else. How could the connecting rods not get in a bind with the shaft moving that much? Is there a simple explanation to this that I have overlooked or do I have to take the engine off, open it up and inspect it?

You know, I wonder if this can happen in reverse. As it, something forcing the crank up, wearing at the top case. I have the same engine but a 18 hp in a Deere 325. For me what happened, oil began flowing out of the lower crank seal down over the pto. Even did the same after I put in a new seal. But only after the engine gets good and hot, like 15 minutes of mowing. Won't leak if the engine is cool and off.

Right below where the seal rides on the crank, the crank reduces in diameter. And I mean like a 1/16"
Of a inch. What I'm thinking is happening is after the engine gets hot, something causes the crank to rise a bit and the seal no longer touches the crank but is now at the smaller diameter allowing the oil to pour out.

Does this sound like what could be happening? I've checked the PCV hose into the air box and it doesn't seemed clogged cause crankcase pressure. And to be honest, this tractors not at my home and really haven't checked to see if there is much up and down play.

I did locate a fh500v which I think will work in my tractor which has a fh531v but if it's something that I can fix on this engine I'd sooner fix mine and not buy another. Tks for any input.
 

bertsmobile1

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The top seal need to be fairly high in the case so as not to block off the oil drain.
OTOH the lower seal needs to be up tight against the case to keep it out of the way of debris.
The crank will float a bit depending upon the deck position.
If the deck pulleys are lower than the engine pulley the belt will pull the crank down if higher the opposite happens
 

cdestuck

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Oct 9, 2013
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The top seal need to be fairly high in the case so as not to block off the oil drain.
OTOH the lower seal needs to be up tight against the case to keep it out of the way of debris.
The crank will float a bit depending upon the deck position.
If the deck pulleys are lower than the engine pulley the belt will pull the crank down if higher the opposite happens

That's interesting. Nothing as changed as to the mower pully but anything is possible. But I'll put it back together but leave off the deck, run it around and see if the leak comes back. Tks.
 

arch252

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Feb 2, 2014
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I picked up a used cover on Ebay for $30 shipped, replaced the gasket and bottom seal and it runs great.
 
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