Replaceing keyway timing is off

Yes there is a keyway on the spindle. That is why there is a keyway there so you do not break the engine inside.

Hallo, I'm looking for a repair manual for 128802-1724-B1 Briggs and Stratton engine. I'm struggling with a the governor setup/ adjustment.
Any help is appriciated,

Frank

The timing is set on these machines the only thing that would disturb the Timing is if you hit something that caused the engine to Stall quickly. If that's the case, you probably broke the Keyway under the Flywheel. Have to pull the Flywheel and replace the keyway.

There is no timing adjustment the flywheel is Keyed with a groove and so is the Crank shaft. The coil is mounted stationary so the timing is preset and should never be bad unless the Keyway broke and the Flywheel shifted.
If you hit something that caused the engine to stall abruptly then the keyway may have broken...Just replace the Keyway

When you whack something that hard and the engine stops immediately 99% of the time you sheared the Keyway between the Flywheel and the Engine crank. When this shears, the flywheel shifts which throws off the Ignition Timing. You need to take off the Recoil starter and then take off the Flywheel, Any small engine place will have a keyway replacement. The keyway Cost pennies

try again my explorer locked up ,right front pulley behind it is the timing gear which is locked into place by a keyway ,this keyway wears and rattles plus the timing gear so the timing is out and the valves hit the pistons ,result back pressure from the bent valves ,the keyway and on the front of the timing gear is another roll pin into the crank nose and they all break here allowing the keyway to chomp away at the timing gear and woodruff key .Result an expensive repair on this diesel engine

Hello, What has likely happen is the keyway (Sears part # 123583X) fell out. Verify this by:

setting the parking brake
lifting the side that you removed the wheel from
turn the wheel by hand

If it turns and the axle does not then the keyway is missing.

The part costs somewhere around $3.00 from Sears Parts.

To replace:

remove the snap ring and outer washers
turn the wheel by hand until the keyway channels line up
slide the keyway into the channel
replace the washers and snap ring
test by ensuring wheel no longer turns without the axle

I also recommend that you go to your local auto parts store and get some "antiseize". Put some on the axle before you replace the wheel that will keep it from rusting and making it near impossible to remove next time. I know Autozone sells it in small packets for about a buck-thirty.

I hope this helps. If it was useful please vote yes. Thank you!

Make sure the motor is on TDC compession stroke when you take it apart.
I'm skipping the tear down because if you want to adjust your timing, im assuming that you already
have it apart.

On TDC place the cam in the head so that both valves are closed.
There should be marks on the cam gear.(cam gear is attached to the cam)
Those marks should be parellel with the head.
While holding the cam in its slot in the head, carefully put the timing chain over the cam gear. You make have to pick the back of the cam up so the front leans forward enough to allow the timing chain to go on.
Once timing chain is on, double check that the motor is still at TDC and that the cam gear marks are parellel; with the head. if not you may have to go one tooth either way to get parellel.
If Motor is still on TDC and your timing marks are good, then your done.

Put the valve rockers back on and the timing chain tensioner, adjust your valve clearance.

With then spark plug out, turn the motor over by hand and watch the valves open and close, if anything is in a bind or if feels tight then your 180 degrees out which means you had you cam in upside down. Turn the cam over 180 degrees and your good to go.

The rotor is keyed so the only way that could go out of time would be if the keyway is sheared, hence the rotor would move retarded or advanced hence back fire out exhaust or intake.

If rotor keyway is sheared, you'll need a puller to pull off the rotor and replace the keyway.
It only goes on one way. On The Keyway.

If your CDI isn't working it will have to be replaced.
If your signal generators isn't working it will have to be replaced.

Your keyway might be cut. The keyway is the timing of your motor. If its cut, the motor will either run rough or not at all. If keyway is ok, check your blade for balance. Take blade off machine, hang on a nail straight across, if it tips either way, its out of balance. Have it rebalanced or replaced.

What can cause this is a very worn crank shaft keyway, a loose flywheel nut or a worn out flywheel keyway. These are the only causes for a flywheel key to shear. If the crank shaft keyway is excessively worn there is no amount of flywheel nut tightening that will stop the flywheel key from shearing. The only fix at that point is replacement of the crank shaft. The same thing goes for the flywheel keyway... It is worn out the only remedy is flywheel replacement.

The only other thing that causes flywheel keys to fail is a sudden stoppage of the engine. Most of time this only happens to lawn mowers then the operator hits something like a mini tree stump or a large rock.

Thanks for using FixYa,

Kelly


I have seen both the crankshaft and the flywheel keyways worn to the point that both had to be replaced. In the event that both have failed, the replacement cost with labor if you have it done is a repair shop can be 60 to 70 % of the cost of a new engine.