L111 won't turn over - hydraulic lock?

[Needleroozer]

Turn the key, you can hear it try, nothing happens. Put the battery on a charger overnight, no change. Battery's over four years old, bought a new battery, no change. New batteries aren't always fully charged, put new battery on charger, no change.

Time for serious diagnostics. Pulled the plugs; one oily one dry. Turn the key and the engine spins like nobody's business. Put the dry plug back, still spins. Put the oily plug back, won't crank. Apparently I've hydraulically locked that cylinder. How do I fix this and is my engine trashed?

 

[bertsmobile1]

Start by pulling the rocker covers off and checking / adjusting the valve lash
Expect to see a problem on the oily side
Worst case will be a damaged piston or rings
Engine is repairable unless the bore has substantial damage .

 

[Deleted member 97405]

Definitely check the valve lash as Bert suggests. The camshaft has a compression release built into it. I can't remember if the release is built into the lobes or if it's the spring arm on the camshaft on this engine, but a few thousandths of an inch can make the difference whether the compression release works or not. If the valves move up and down, and the pushrods aren't bent, adjust your valves to specs, and see if it cranks. Here's hoping your cam lobes aren't worn or the compression release mechanism didn't come off the camshaft.

 

[slomo]

Pulled the plugs; one oily one dry. Turn the key and the engine spins like nobody's business. Put the dry plug back, still spins. Put the oily plug back, won't crank. Apparently I've hydraulically locked that cylinder.

No hydro lock if it spins over with no plug. Unless in one minute that cylinder got full enough of oil to hydro lock it. Doubtful.

More like a blown head gasket on one oily cylinder. Either neglected cooling fins or the infamous Briggs head gasket issue.

1.Inspect valves. Valves way out can cause starting issues.
2.Retorque good head to OEM specs.
3.Pull oily head and check head gasket.
4.Check for proper oil level, tires at proper air spec on flat ground.
5.Pull oil dipstick, smell for fuel.

 

[sgkent]

Do these engines have a compression release?

 

[slomo]

Do these engines have a compression release?

Think this is a 20hp Briggs, not for sure. I would say it does.

 

[StarTech]

They came with 20hp Intek V-twin. No compression release on the camshaft but if the valves are out of adjust can can starting problems.

Just note one of cylinder has a lot of oil or fuel in it will hydrolock as you can't compression a liquid per say.