OT JD 160 Lawn Tractor (pic)

Have one that will run fine till it gets hot, then
won't handle a load and wants to quit. Thinking it
is the Regulator/Rectifier it was hot to touch so I chilled it with a spray of WD40 and it ran fine for a bit. Did this a couple times.
Do those things fail with heat? Is that what you
would call a Coil? Was told on the lawn tractor page that the regulator only charged the battery.
Thanks for any ideas.

If it is like our 140, it had a separate ignition system, points and coil. That module is a rectifier/voltage regulator. I would check the battery for dead/shorted cell. Then tchek or repalce the module.

Great you found the voltage regulator!!!! LOL now the bad news. It DOES NOT have a thing to do with the ignition system unless the battery goes dead. It should be warm/hot when your mower is running. Notice the fins cast into it??? They are to cool it.

If you shut it off to cool/spray the regulator then that is allowing the igniter to cool enough to have spark again.

Your problem is the igniter #4 above. It is on the right side of the motor. Yours could be two types. One has two wires coming off of it with one being grounded and the other hooked to a wire that goes to the coil. The later type just has a terminal on it for the coil wire and the mounting screw grounds it. The new one you get is the newer style.

The coil is under the shield by the flywheel. The coils very rarely fail. The igniter do fail. when they do they act exactly like your problems. Run great and then sputter and die. Let the mower set for maybe 5 minutes an it will run again and then sputter an die.

Now the bad news. The new igniter number is AM131398 list price $75.29. That is what it will take to "Fix" your problem. The voltage regulator is not your issue now. It maybe in the future with you spraying it with WD-40. The cold shock may have damaged it.

lots of the old tractors have a problem with vapor lock or boiling the fuel because of the ethanol in the gas plus older engines run hotter as they wear. I had to move fuel lines to a cooler route and use an electric pump