Flywheel key broken - Craftsman Garden

Most common issue with this engine is a broken flywheel key. The key is a small piece of metal used to locate the flywheel to the crank. if the flywheel nut is not to the right torque it can slip breaking the key and putting the ignition timing out. Your symptoms fit this.

This page shows single cylinder engine info, but it is relevant. I quick search on YouTube will show many videos on how to check and replace this key.

How to Inspect Flywheel Key for Replacement Briggs Stratton

With the flywheel key broken you need to remove the engine cover first. This may involve removing the fuel tank as well. There should be a nut on top of the flywheel that needs to be removed. After this is off the keyway is exposed. Replace it and replace the parts in reverse order.

Lawmowers have a coil mounted along side the flywheel. You have to remove pull cord assembly, then remove flywheel nut. now the coil is exposed. most of the time rust on the flywheel is the only problem. Clean with 120 grit sandpaper. Loosen the coil screws so the coil can move in and out, then palce a match-pak carboard flap between the flywheel and the coil and snug down the screws. you should be all set. Now make certain to check the flywheel key to see if it is bent or broken. These keys are made of soft metal to protect the crankshaft from being damaged. So replace the key if damaged or broken. This should solve your problem. To test the coil you either need a ampmeter, or you can pull the cord while holding sparkplug wire 1/2 inch from engine bolt and look fo spark while pulling the rope. Good luck. Don't forget to remove the matchbook from the flywheel after setting gap, which is .010 thousands of an inch.

Sounds typical of a broken key on the flywheel which allows the timing to fire at the wrong time. Flywheel on a mower is under the pull start mechanism housing. Caused by hitting something solid with the blade and the momentum of the engine shaft cracks or shears the metal key part. Remove the flywheel carefully and put in a new key.

yes it will its on tight, they are easy to remove though stick somthing under it to pry with now with a hammer hit the other side and top of the flywheel turn round and round till it pops off

check key switch first, and fuse.

Not sure if I understand. Do you mean the complete flywheel inside the engine? Or are you talking about the impeller that draws in the air for the blower? Please repost if you mean the impeller, and explain a bit about what happened. If it's the engine flywheel, you basically remove the shroud/body until you get down to the flywheel, remove the nut holding it on, and remove the non-broken pieces. Then, put the new flywheel on, being careful to line it up with the keyway on the shaft. You can easily damage a new flywheel if you put it on improperly.

give it a shot of starting fluid, if it fires, it has a fuel problem, if it does not fire then you have a broken flywheel key.You will have spark with a broken or partially broken flywheel key, but your timing will be off and it will not run. good luck

remove the nut that holds the flywheel on.right hand threads.once the nut and starter hub is off the keyway will be visible.you can tell if it is broken then.if it isn't put the hub and nut back on.....problem somewhere else.if it is broken...take a small hammer and tap the flywheel on the oppisit side of the keyway.usually only takes a couple of hits from the hammer.once the flywheel is off the key comes right out of the crank shaft......replace the key,reinstall the flywheel.(some times you have to hold the brake off so the flywheel will slip all the way on shaft) install hub and nut.hope this helped,let me know........................

Key should be available separate