I have a 14 HP B&S Murray Riding Lawn Mower that won't crank. It is an older mower but has been very good and is well maintained. When I try to crank it the flywheel turns a half turn or so and seems to be locking/hanging up. I have just purchased a new battery. No luck. Seems this happened once before to find out that the magneto or it's mount (?) was loose and slid over stopping the crank from turning. When it did start it sounded as if it was scrubbing/rubbing on something. Now it won't crank at all and won't even spin. I can bump the ignition at times and it will turn a quarter turn or so then stop turning other times it just makes a clicking sound.
Anyone know what the deal is. HELP!!

Hmm I'm not real great with engines, but, you didn't mention anything about checking/replacing the spark plugs, that would have been one of my first guesses

There are also some other postings similar to this one, with suggestions like "check battery cables, could be corroded" or:

"With engine off. Turn the cover on the flywheel backwards about 1/4-1/2 turn and then try and start. Many times it hold compression if the valves are loose and the piston ends on the compression stroke." -esquire1

Sorry left that out. I have changed out plug and manually turned the flywheel back about half a turn. Still no luck... seems to be hanging up or simply stopping.

Does it hang up 'solid' - like it's physically jammed, or 'soft'?

There are 2 possible reasons the engine won't rotate - 1) Something has moved and jammed it or 2) the cylinder is full of oil/fuel, and has hydraulically locked.

Eliminate number 2 by removing the plug and cranking the engine. If it still won't turn, there's some sort of mechanical reason. Magneto armature loose and fouling flywheel is most likely, followed by alternator stator (requires flywheel removal to check).

If it WILL turn, check what is blown out the plug hole by cranking. If it's fuel, you have a leaky carb inlet needle. If it's oil, check it's not over-filled.

Had same problem once. The rectifier (under the flywheel) had vibrated into several pieces and was locking up the flywheel when pieces interfered with turning. Afraid you are going to have to remove the flywheel to findout if this is your problem

Quote:

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Originally Posted by MowerMan42

Eliminate number 2 by removing the plug and cranking the engine.

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Be careful when you do this.

Put a rag or something over the spark plug hole to catch whatever may come ot. One time I just cranked it over and it sprayed out gas which was in the cylinder. It was ignited by the spark plug wire and started a fire on the front of the mower. Luckily I was able to put it out with little damage.

So, like I say, Be careful. Move the spark plug wire way out of the way and cover the hole...