Craftsman lawn mower refuses to start after being used for a short period...

Family 7BSXS.1901 VH. 277307 :=: Model 917.388109

This machine was given to me some years ago by a nephew of mine but never understood if it had any issues with it. Certainly, there're at least 2 things missing: a top cover for the flywheel & a "cover" near the carburator. In any case, have been using it without any problem until a few days ago...

After using it for about 15 mins stopped it for piling up some grass with a rake & noticed some gas drops falling fron the top of the gas tank (there's a small crack near the gas cap). Didn't care much at the moment and forgot about it.

When started it again noticed that it was not running at the correct speed (slower) & it stopped ~10 times in a 10 mins time frame where the grass was much lower than before...

After raking for about 15 mins the mower never started again. Took out the spark plug and a quick visual inspection showed me nothing wrong there. I suspected a gas overflow to the cylinder since the crack augmented the gas tank ventilation quite a bit (1/4" crack).

Today tried to put some tape over the cleaned crack & give it more than a dozen trials but it doesn't start.

PS. About a year ago it hit a piece of concrete and the blade was torned so much that I replaced it (maybe the one I used had a turn angle or twist more pronounced than the original one); who knows there's a problem...

About 3 months ago it hit a root of a tree and stopped right there. After inspecting the blade it seemed ok but, at that precise moment, it didn't start but it had a very low gas level and, since it was late I didn't put any more gas to check it. Nevertheless, this time it started normally as always.

The other day I also took out the top cover to ckeck if it had a broken wedge but it seemed ok and it required a puller for taking out the flywheel which I don't have.

Hope I've given enough info for a possible promissing reply! Thanks in advanced!

 

Sounds to me like you're on the right path in checking and probably replacing the key between the crankshaft and flywheel. Most small engines I have worked on had holes in the flywheel that you can thread bolts into to press it off.

 

What does "Nothing wrong" look like...

When it won't start does it have spark?

 

Thanks for replying, BFHFixit!

When I looked at the spark plug it seemed clean & dry. Yesterday took it out, mantained depressed the safety "feature" for grounding the electrical ignition and the break for helping reduce the rotation of the flywheel & with the spark plug at a convenient location pulled the string ~16 times and saw sparks jumping at it. So, I discarded an electrical problem.

How to proceed from here?

 

If the flywheel key is sheared you will still have spark, it will just be at the wrong time. Have a good one. Geo

 

Thanks for replying, geogrubb!

You were very correct!!! I took the flywheel out & it was broken in two halves. Relpaced with another & now I'm distilling some sweat.

The only issue is that need to take the flywheel cover out because the torque used was insufficient... Hope this's the last time I need to do this.

 

If you ever need to lock the engine for torquing the flywheel nut remove the spark plug and load the cylinder with small rope like starter rope, leave a little hanging out, when the engine ties to compress the rope the engine will lock and you can do whatever need done, when finished back it off a little and remove the rope that way nothing gets broke. Have a good one. Geo

 

Never heard of this idea before, geagrubb!

 

Old cotton clothesline is good to keep around for this purpose.