Problem with 1997 15 Johnson overheating

[powerplant]

Good day to everyone, I hope that someone out there can shed some light on my problem.
I got the engine out of storage and set it up in a tank to make sure that everything was working properly.
After 18 months in storage it started on the second pull, I let it run for a couple of minutes and shut it down since I wasn't getting
any water peeing out. Took it apart and replaced the impeller, reassemble restart and get a strong stream.
Put the boat in the water run around for about 20 minutes when suddenly the nice stream turned into a high pressure jet of water and air.
Anyone who has drained water out of a large air compressor will know what I'm describing.
I shut it down and rowed back to the ramp.
I started it today and everything seems normal, I'm hesitant to let it run for long don't want to risk causing a total meltdown.
Would appreciate any insight into what might be happening.

 

[brutus]

Good day to everyone, I hope that someone out there can shed some light on my problem.
I got the engine out of storage and set it up in a tank to make sure that everything was working properly.
After 18 months in storage it started on the second pull, I let it run for a couple of minutes and shut it down since I wasn't getting
any water peeing out. Took it apart and replaced the impeller, reassemble restart and get a strong stream.
Put the boat in the water run around for about 20 minutes when suddenly the nice stream turned into a high pressure jet of water and air.
Anyone who has drained water out of a large air compressor will know what I'm describing.
I shut it down and rowed back to the ramp.
I started it today and everything seems normal, I'm hesitant to let it run for long don't want to risk causing a total meltdown.
Would appreciate any insight into what might be happening.

Thermostat is struck, won’t open when at temp

 

[powerplant]

Thermostat is struck, won’t open when at temp

I hope you're right, I went to Sherwood marine and picked up a replacement this afternoon.

 

[sly_karma]

I hope you're right, I went to Sherwood marine and picked up a replacement this afternoon.

Easy to test a stat, just put it in a pot of water on the stove and heat it until it opens. Check your manual but typically OMC stats open at around 143 F. A cheap instant-read meat thermometer will give you an idea of water temp at point of opening.

 

[BC Coast Pilot]

I hope you're right, I went to Sherwood marine and picked up a replacement this afternoon.

I have 2 of those motors i don't use anymore one was a runner the other was parts motor.
Both extra long shaft.
Let me know if you're interested