Possible the gas all leaked into the crankcase and it is now hydraulically locked?

Last year (maybe the year before, time flies) gas had ran in to the oil. I had to replace the carburetor then and I put a valve on the fuel line, but of course I forgot to close it at the end of last season :-/

The oil looks fine, so I don't think there's gas in it this time. And where I filled up the gas tank yesterday, it still looks full today. So if it's leaking in to the motor, it's going slow.

So today I took out the spark plug. I didn't have gas pour out or anything, and the flywheel still wouldn't move when I turned the key or by hand. I don't see any oil coming out of the exhaust, either.

Am I right in understanding that, if it's hydrolocked, oil would be in the exhaust?

Maybe I should use my air compressor to sort of blow in the spark plug hole and force liquid out?

This is an irritating one, it was purring like a kitten in November! The only other thing I can think to do is remove the flywheel and see if something has gotten inside of the motor >:-(

By chance , do you have a blade brake on that riding mower.

@always_beezee, not that I know of.

@kevin9408, I checked today and the pulley directly beneath the engine is definitely locked up, too. I couldn't take the flywheel apart because the nut was too big for my sockets, so next up is to borrow a lug wrench and see what's going on under there.

I PB Blasted everything today, but that didn't help. And I gently tapped things with a rubber mallet, also no go. I'm starting to run out of options, so if there's nothing under the flywheel then I'll pull out a pipe wrench and give it a shot! The shaft is just round so there's nothing to grab with my channel locks, but a pipe wrench should grab it.

I might not be able to do it until Friday, but I'll keep you posted! If you think of anything else before then, I'm all ears :-D

Another update... I drained the oil, there was definitely gas in it! So I drained it the best I could, filled it up with 10W-30, drained that, then filled it up again.

So that's the source of the problem. Now the question is how to get it unlocked.

The nut on top of the flywheel is bigger than the lug wrench! So now I'm not sure how to get that off.

I tried using a pipe wrench on the pulley underneath, but there are guide bars for the belt that are completely in the way.

Next thought, maybe take off the belt and go buy a strap wrench to use on the pulley itself?

Good news!

It took me a few days, but I bought a 6" strap wrench yesterday. And like I described before, I took the belt off of the pulley beneath the motor, strapped on the strap wrench, and pulled it in the reverse of it's normal turn.

It took a little pressure, but it popped free in just a few seconds!

And then it fired right up :-D

I had to turn it off to put everything back together (which took about 30 minutes), and then it was eatin' time. So THIS time I turned the fuel valve off manually, and I'll try it again on Monday to make sure it runs right. But so far so good!

Thanks all!

Does this mean your not going to get a robotic mower? My issue with the robotic mowers is having them stolen right out of the front yard. They run so often even when one's not home that it would become a tempting target for any person walking by, from 12 to 70 years of age. There is always one or more in any area wiling to steel to sell or they just want it, dogs get stolen all the time.

I have definitely NOT ruled out a robotic mower! This mower probably won't last much longer, anyway, so I'm thinking about buying a robot for the back yard (fully enclosed), and then use this for the front yard and for light hauling. That should extend its life by a few years, and would save me a lot of stress on having to maintain the dog's play area / toilet (the back yard).

I'm in an economically depressed area, too, and we have more meth heads than you can count! So yeah, thieves are a concern :-( Luckily, I live on a pretty private street with only 2 neighbors past my house, so there are no walkers and few drive-bys. So the back yard SHOULD be relatively safe.

Have you considered buying security cameras? I have 3 Eufy cameras in the front of my house, so if anyone comes up it's recorded and I get a notification!