2000 Nissan 25 stops running

Customer bought a 2000, 25 two stroke. Said it runs for 10-15 mins. and shuts off and will turn over but not crank. He waits 1 hr. and it cranks and runs 10-15 mins. same thing. Cold compression test 150 an 130. I ran motor on muffs( taped off water pick up on cav plate) had a strong pee, ran at 3300 rpm, for about 8 mins pee stream was getting weaker , like air in coolant system. Shut off motor. Shot head with infrared temp. gun and head was 210° F, this is a tiller motor , no heat alarm horn and no temp. sensor in head. I didn't do hot compression test. I pulled termostat cover off and someone had torn apart termostat, no spring , his round part with rubber seal. So obviously seller knew it was overheating and punched out termostat. Question is motor known to get pin holes in heads combustion chamber. I would think if blown head gasket I'd not have good compression when cold. Another question if motor is getting hot enough to shut down how does it not seize a piston ? Any replies are appreciated, thanks
We get maybe 1 Nissan every 2 yrs.

You likely have an NS25C3. Year is irrelevant.
If it is turning over, the motor is cranking. Maybe not starting.
Is it a long shaft version? Was it stored outdoors? If yes to both, you may have a collapsed water pipe.
Those heads are not known for getting pinholes.
Definitely want a new thermostat, probably a new wp kit as well.
Overheating can cause the motor to have too much friction, then when cooled, be unstuck.
Running without stat can cause it to run cool, but can also cause overheat.

I'll be at work at 9:00, customer said impeller had been replaced. Is water tube plastic ?
Yes it's a long shaft, yes I think your rite on model. I wrote down yesterday. Say head is not know for pin holes. Thanks

Water pipe is brass or copper. If long shaft and drain clogged, could freeze and collapse water pipe. That was an issue with early 4-stroke 25 and 30 motors.
Never do just an impeller. Always do the complete kit. Cost about the same, pumps better, lasts longer.

Thanks, model ns25c3 serial. 58931
Do u happen to no tube part # ? I haven't dropped lower unit yet.

Thanks, does power head have to be removed to change tube ?

Dropped lower unit , water tube looks fine. Will do more looking tomorrow.

How does the water pump look?

Water impeller and housing looks good, it new had been replaced by another shop 6 months ago. Grommet and o-ring on water tube an rubber grommet on housing.
Installed new termostat, gettin steady pee stream not strong but steady. Infrared gun watching head temp. It climbed up to 200°F. I'm thinking maybe water passages in power head.
I ran wire up water tube and compressed air.

If the previous impeller disintegrated, blowing air back through the telltale might dislodge it. If corrosion in the head, etc, salt-away might help, but manual scraping after disassembly is usually more effective.

Thanks, going to drop lower unit again a put compressed air in telltail.

Pvanv thanks for advice, found problem, dropped lower unit shot air in telltale got a little piece of rubber, pulled thermostat housing, shot air in 1/2 inch passage next to thermostat it was plugged at the bottom with grass. Pulling head now.

Pics.

Can't post pic.

So an old impeller had a bit jammed in there, plus crud in the head by the stat. Maybe once that's all cleared, it will cool OK.

When stat opens it lets water flow in. 1/2 tube that runs on top of head (casted ) that straight tube passage was completely clogged with grass and weeds. If I could post pictures . I'd show. It was a palm full.