If your engine had been sitting around for a while and if you don't flush it...that's one good way to kill it.
Don't worry , you can get a repair kit for it. (sleeving and piston set)...later.
When your engine starts running hot for no particular reason..or perhase that's what worn out sleeving/piston do.

When those gunk particals break up..they like to fly around and hit the glow plug coil and kill that too.

if you had ever taken an engine apart after it's been sitting for a while...you'll notice a line of gunk on the sleeving
where the top the piston was sitting. If the gunk gets cuaght between the sleeving and piston...it likes to make scores
on the sleeving and piston.lol

After run oil is nice...but ya see, that if it works it's into the carb orifis too.lol

Remove all plastic parts (o rings) and soat it.
If you shine a flash light into the bearings...you'll notice corrosion build up on the balls.

Remove the needle valve so whatever cleaner will work it's way into the carb's orifis.

Well...if your fuel is old...half air/half fuel.lol
Do you ever notice condensation or meldew in the morning on the hood of your car ?lol Ya see...that samething happens if you let
your fuel sit outside or in the garage.lol