pto belt comes off cub cadet model 123 with 42" deck

[CubDieselFan]

Try this, clean your points with a old style fingernail file and then set them to 0.020. I cut grass for the neighborhood when I was a kid. I used a 102 and I would have to do this a couple of times a summer. I put a lot of hours on that Cub.

[knucklescraper]

I sanded the points with 320g sandpaper. The nail file was an excellent suggestion CubDeiselFan and I have one but it has a point on it which got in the way.

I checked the timing and it was the same after sanding. Almost perfect. The 'S' is slightly higher than centered in the viewing hole. But that's how it was before I had the stalling issue.

When I mowed the grass, same stalling issue after about 1/2 hour.

Perhaps it is the coil after all. The coil wasn't as hot this time as other times the tractor stalled (it was a cooler day). Maybe it is just getting worse.

It is quite consistent at about 1/2 hour for the first stall whatever is causing it.

[Billy-O]

Maybe it's not the coil.... Maybe you starved of gas because the gas cap may not be vented properly.

[Grandpa53]

Make sure you have good airflow across cylinder and head from flywheel fan. If you are mowing weedy areas the flywheel screen needs to be checked every few minutes and cleaned of weed debris if any has accumulated.

[knucklescraper]

Billy-O, the cap holes seem clear but I happen to have a spare cap so I'll try that on the next mow.

Grandpa53, I'll definitely keep an eye on that screen. Maybe there is some other issue with the flywheel itself.

Thanks for the suggestions. It will probably be about a week until I mow again.

[jbrewer]

I'm often wrong, but whenever there's a stalling problem, I like to think it's a fuel issue. You can test the cap by just leaving it a half turn loose. It doesn't take much to get air in there from the small amount of gas these engines consume.

When it finally shuts down, do you ever get a backfire as it's winding down? Does it cut out all at once or just start losing power, engine pitch changes sound, and then dies?

[darkminion_17]

Check the valve lash....spec numbers are on the tag.