D110 won't turn over

[Snee Oosh1]

John Deere D110 2013 mower. If I take the spark plug out it turns over fast, but oil sprays out. If I put the plug back in, it will not turn over.

 

[bertsmobile1]

Usual cause is carb float not shutting off the fuel which ends up in the sump over filling the sump & thinning the oil

 

[Snee Oosh1]

Usual cause is carb float not shutting off the fuel which ends up in the sump over filling the sump & thinning the oil

Thanks. I will check that out.
Any other ideas?

 

[bertsmobile1]

One thing at a time
Dip the sump, check the level then feel the oil and smell it.
Get back with your results
I have no intention of rewriting the entire JD Technical manual

 

[Snee Oosh1]

I checked again. The oil level is correct, and it smells like oil. Does not smell of gas.

 

[Snee Oosh1]

I removed the hood and the flywheel cover for better access, and removed the gas line.
With the dipstick removed, and the spark plug removed, when you crank the engine lots of pressure and oil blows out the dip stick cover.
When you turn the flywheel by hand, with the other hand covering the dip stick cover, you can feel the suck and blow on the end of the dip stick cover. Does any of that info help?

 

[bertsmobile1]

Yes.
You have ruled out the most common & easiest to fix option
Most of the internals are lubed by splash so yes oil should splash out the dip stick tube.
And of course the piston is an air pump so as it goes back in the engine, the air under it has to go somewhere.
It should go out the breather which is the next thing to check.
The starter is not strong enough to overcome full engine compression so there is decompression built into the engine.
Remove the rocker cover & check the valve lash.
On OHV engines it gets bigger over time and that defeats the compression release.

 

[Snee Oosh1]

The intake valve lash is .006 in, and the exhaust valve lash is .007 in. The manual says intake .003 to .005, and exhaust .005 to .007. Is this far enough out of specs to cause no compression release?
I was told that about 2 years ago the mower was running fine when it backfired when they shut it off,(which evidently it did not do normally) and it never would start after that, so it set there until last week when I got it. The hour meter shows 185.5 hours, so it seems there should be lots of good hours in it if I can get it running. Thanks for the help!!

 

[bertsmobile1]

That will depend upon things like cam wear
As you rotate the engine watch the rockers .
You should see one of them close then reopen just a tiny amount then close again .
That tiny reopen is the decompression

 

[Snee Oosh1]

I cannot see or feel any reopen on either rocker.