Hey everyone, I'm back again with yet another problem needing advice.
I have a Murray riding mower with the 12 hp i/c briggs vertical shaft engine on it. The engine runs great, or did until this afternoon. I was "raking" some leaves in the back yard with the mower, more or less driving around in circles to pile them up. I know its lazy. Anywho, when i was done I turned off the mower and started burning the leaves. Well I went outside a few minutes ago to move the mower under cover and the engine will not turn over, the starter just runs, but doesn't engage the flywheel. This engine does not have a pull start. I know that the motor didn't lock itself up because I can spin it with my hands. So where does this lead me, starter issue right? Whats wrong with it? When the clutch is pushed in and the key turned to start the engine the only thing that happens is the starter runs, but it is not catching the flywheel. Any help will be most appreciated. Thanks for all you do . This forum rocks.

Justin

Check the pinion gear on the starter, it may be stuck on the worm shaft of the starter drive, or it could be stripped as most of these are plastic.

i tapped on the starter with a hammer and it started up. Where does this point me? need to rebuild the starter? Sticking gear?

Not a good idea to hit the starter, the magnets in starter are ceramic and they can crack or break if you do that. The starter drive is probably sticking and may have wear. It would be a good idea to remove the starter from the engine and inspect it the bushings on the armature may also have wear and could be loose, but more than likely its the starter drive.

how much is it to have one of these rebuilt?

It depends on what is wrong, to have the starter drive replaced parts are around $20.00 + labor unless you do the work yourself

ok thanks , I will check into it. there are a couple small engine places around here.

you could just take the starter off and replace the gear. its an easy fix. just punch the little pin out on the top and replace gear.

Your starter sounds fine. It sounds like the gear isn't being thrown into the flywheel. Ever seen one of those yankee screwdrivers where you push down on it and it screws the screw in? That's the way these starters work- a forceful spin makes the gear get thrown upwards. Often times dirt and crap fouls up the slide that the gear travels on. See if you can clean and grease the starter shaft first, and if that doesn't do it, take engine man's advice and get another gear.

Briggs and Stratton advises against applying oil or grease to the starter gear or helix. Dirt can mix with the lubricant and cause the gear to stick, and if it remains engaged while the engine is running, your starter can be damaged.

If gear is plastic and corners rounded off, you can flip gear over to use the other side.

Take the starter off, leave the electrical hooked up and engage the starter to determine if the helix shunts the gear up. If not, inspect the drive for foreign objects, burrs or broken parts. If it works just flush it out to remove any debris. I use teflon spray or in a pinch a light blast of graphite (not my first choice) for a reasonably non attractive lubricant after cleaning. Triflow works good. Most starters are expected to grind a certain amount of trash due to their working environment but the cleaner the better. You probably got some goob in the starter gear drive. Servicing the starter helix, although not considered routine maintenence, is fairly routine if nothing's boogered up.

I've replaced several of these over the years. The gear is plastic therefore it wears and not your flywheel gear teeth. Over time the gear and the drive wear and the gear may not engage or it may bind up in the flywheel and not release. When this happens you may think your engine has seized because the starter won't run and the engine will be bound up and won't turn by hand either. If the gear binds in the up position, you basically have to work the engine around enough until the gear drops down the spiral drive, you cannot hope to drop it by turning the gear backwards on the starter- the engine has to turn. Please take all safety precautions to ensure you don't start your engine by accident if you have to rotate it slightly.

It's an easy fix although on some models the inside bolt for the starter is up under the flywheel. Once you break it loose with an open end wrench, you'll need to back it out with two fingers up under the flywheel. There is a groove up under the flywheel deep enough to back the bolt out enough to remove the starter. You will need a small drift or punch to remove the pin listed in an earlier post. I just paid the listed $20 yesterday for the kit with includes the new gear and drive. It's about a fifteen minute job after the engine cowlings are off.