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

[knucklescraper]

I haven't received the parts I ordered from CC Specialties on 4/28 yet. Is this a normal length of time for an order? I sent a couple emails and left a voicemail but haven't gotten a reply which is concerning.
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In the meantime, a neighbor gave me some belts he had. One was an unused 490489R2. I put that on and it stayed on. It measures 0.460" wide. The belt I had been using measures ~0.435" wide for what that is worth.

I mowed the front lawn (weeds up to my knees, grass a few inches lower) without incident. I thought the engine was running hotter than usual and gave it a rest before starting on the backyard.

The grass and weeds in the backyard are more dense and higher than the front yard. The tractor was definitely working harder. There was a noise I interpreted as coming from the pto belt as the load increased. I compensated by raising the deck and or going more slowly. Nevertheless, as I continued mowing, the sound got louder, the engine got hotter and threatened to stall many times before it actually did stall.

I had difficulty restarting the tractor and engaging the mower deck had to be done very gradually or the engine would start to stall. Eventually, when it stalled again, I couldn't restart it. A couple days afterwards, I still can't start the tractor. I've replaced the spark plug, cleaned the fuel bulb, and have eliminated the battery as the culprit. I'll check the fuel line for clogs next and probably look at the carburetor after that if necessary.

Does anyone else have any recommendations?

[darkminion_17]

Bad coil or condenser, Any mouse nest under the tins will make it hot. The belt is too short by 1" are the pulleys rubbing against the axle? Check the mower deck spindles, do the spin freely?

[knucklescraper]

Finally reached Charlie at CCS. The parts were sent out the day after I ordered them but it sounds like there was some sort of issue with the shipping company. He's looking into it.

[knucklescraper]

The belt was a breeze to install and there was a gap between the pulleys and the front axle. Plus I tightened the tensioner a bit which draws the pulley assembly away from the axle.

I'll check your other suggestions tomorrow. Thanks a lot.

[finsruskw]

Ideally, the pullies should be in line with one another.

[DSarow]

finruskr can you explain what you mean by the pulleys and their alignment etc,

[knucklescraper]

Over the past couple of weeks when I had time here and there I did the following:

recharged battery
verified spark plug sparks
put in fresh gas
cleaned fuel bulb and fuel line
fixed loose wire on condenser
fixed loose wire on coil
put gas directly in combustion chamber
replaced coil, condenser, spark plug, wire from coil to spark plug, carburetor
At this point, even though I wasn't sure if all the components I swapped in were good, I figured I must not have low compression => blown head gasket.

Checked the head bolts and they were not as tight as they should be. Removed head and the head gasket was blown. I happened to have a new head gasket. I sanded (150g) the head on a piece of plate glass until the sand paper started tearing (maybe for 1.5 hours). Checked behind engine tins .. no debris. Nice and clean. Reinstalled head.

Tractor started up easily. More power. Louder.

But, while mowing the lawn (it is high again although not knee high like last time), after maybe 15 minutes, engine would start to stall. If I shut the tractor off for a bit (maybe 15 minutes) I could mow again for ~15 minutes.

There is no trouble starting tractor.
The grass was a bit wet (last time too).
I think the breather plate is leaking a bit. I remember I didn't have a gasket for it and just used permatex to seal the cover plate. I don't know if that has anything to do with it.
The coil on the tractor now is one of the spares of unknown condition. Maybe I'll try putting the original one back on.

I'll tinker with some more with it.

At least I can cut grass now.

[DSarow]

I believe your coil is a suspect now,gets hot ,shuts down.If you happen to have another coil,the minute it shuts down,do a simple exchange.Sounds like you have worked really hard doing some other critical maintenance items

[knucklescraper]

Thanks DSarow. I'll do that. The coil was hot when I shut off the tractor.

[knucklescraper]

I checked the head bolts. They had loosened a bit from what I torqued them to. Retightened them. I don't know if they will eventually maintain their torque or if it is normal for them to loosen a bit when the engine runs and then maintain that new torque.

Tractor still starts easily. Continued mowing lawn. When it eventually stalled, I swapped in the spare coil I have and continued mowing. It stalled again quicker this time. I guess both coils are no good. I swapped coils back a forth a couple of times but eventually it wasn't worth the effort. I finished the lawn with the weedwacker.

I guess I need to purchase a new coil.