Here is a typical flywheel key replacement. When you remove the shroud on top of the motor, blow it out with compressed air. A dust accumulation around the fins will cause overheating and coil failure. When you remove the flywheel nut, you can usually see if the key is sheared. Reprinted from a prior posting: The customer drops off a lawnmower with a tag that says “The motor stopped and couldn’t restart”. I pull on the starter rope and I hear a scraping noise underneath. The first step is to see if the blade is bent. The blade hub comes off at the same time. Since the blade is bent, along with a broken hub, and the motor won’t start, the usual culprit is the flywheel key being sheared. Unplug the spark plug wire. If you have electric start, disconnect the battery. The top dust cover is removed first, then the gas tank is emptied and removed. The oil fill tube mounting screw is removed and the fill tub is turned to the side, but still in place. The shroud is usually held in place with 4 bolts and after they are removed, lift the shroud straight up. At this point, you’ll have the flywheel in view. It’s obvious that the key is broken. Sometimes a motor will still run when the flywheel is this far out of alignment and sometimes a motor will not run when it is only slightly out of alignment. The flywheel puller tool (Briggs part number 19069) requires that two bolts be screwed into the flywheel. This is difficult without the use of a ¼” X 20 tap, and the flywheel is first tapped. You need at least 3 threads for the bolt to engage securely. Install the tool. There is a nut above and below the heavy steel bar. Turn the bolt into the flywheel until it bottoms out. It isn’t necessary to use the bottom nuts. Use a wrench to hold the bolt head and another wrench to turn the top nut down against the steel bar until it contacts. Do the same for the other bolt and nut. Alternate between the two nuts and turn the nut ¼ turn at a time until the flywheel pops off. When installing the new key, be careful that it doesn’t fall out of the shaft groove when placing the flywheel back on. You will need a suitable tool to hold the flywheel while you torque the center nut. I know that some will use a strong screwdriver to keep the flywheel stationary, but you might end up breaking one of the fins using that method. Sometimes the starter hub which goes between the nut and the flywheel has a tab on the bottom that engages a hole in the flywheel. If you torque to nut and the starter hub isn’t flat against it, the flywheel will break while being torqued. Always refer to a manual for the proper torque spec. Total job time: Less than ½ hour.

The bushings that hold the steering shaft and sector gear shaft should likely have been replaced as well. They need to support the sector solidly. Next, move to the front axle. Do the wheel spindles move smoothly and is there any sign of bent spindles.It is easier to view/ measure with the center of the axle supported and the front wheels off. I assume you would have noticed if the axle was split.

I was able to find the problem. Turn out to be a stuck choke valve. I removed the entire carb and cleaned it. There were a lot of build up grime and dirt in the inside of the carb bowl. I noticed one of the springs on the valve was covered with dirt and was restricting the valve to open freely. A good spray of carb cleaner and an air hose did the trick. Problem resolved.

Have a helper sit on the seat and put the tractor in gear and try to drive while you observe the end of each axle shaft at the wheel. If you see one of the axle shafts spinning inside the wheel hub, the one that is spinning is missing its axle key. The key is shaped like a small bar of metal maybe 1/4" square and about 2" long. Concentrate on the "key issue" and forget about the magneto. The only thing you have done that is related to your described symptoms would be the axle key. Look all around where you removed the wheel to see if you can find the key. If you transported the wheel in the trunk of a car or the bed of a pick up truck..........go back and see if it fell out in transit. If it fell out where the tire was fixed there may be a slim chance that the person found it and is saving it for you. There is also a chance I might win at Powerball.