2 stroke boat motor acting up

[Fatcamp]

https://www.thehulltruth.com/boating-forum/1111666-mercury-40hp-2-stroke-runs-great-but-then-won-t-any-ideas.html

Been reading a ton about these motors as I knew I was gonna get one, 40 50 or 60. When I saw this conversation I thought about your problem. There are a couple other forum conversations that are similar.

 

[weekender7]

It sounds like to me that this motor has been run hot, over heated and now the rings are weak. Had a friend that had the exact same symptoms. He had to have his rebuilt to fix it. The proof will be in a compression test when the motor has been run for 30 minutes or so. First check all 4 cylinders compression when the motor is cold. Write down the results. Then run 30 minutes and check again. If you drop more than 10 pounds in any cylinders you have problems only a rebuild will fix. It is an easy check. You unplug all the spark plug wires, take one plug out and screw the compression gauge in the spark plug hole. Turn the motor over with the key for 5 seconds. Repeat for all cylinders.

https://www.amazon.com/ZJERYL-GULL-Compression-Automotive-Motorcycle/dp/B0BLGNRQFG/ref=sr_1_3_sspa?crid=ZP7N87343M9S&keywords=compression%2Btester&qid=1695092454&sprefix=compression%2Bt%2Caps%2C123&sr=8-3-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[Finch]

It sounds like to me that this motor has been run hot, over heated and now the rings are weak. Had a friend that had the exact same symptoms. He had to have his rebuilt to fix it. The proof will be in a compression test when the motor has been run for 30 minutes or so. First check all 4 cylinders compression when the motor is cold. Write down the results. Then run 30 minutes and check again. If you drop more than 10 pounds in any cylinders you have problems only a rebuild will fix. It is an easy check. You unplug all the spark plug wires, take one plug out and screw the compression gauge in the spark plug hole. Turn the motor over with the key for 5 seconds. Repeat for all cylinders.

https://www.amazon.com/ZJERYL-GULL-Compression-Automotive-Motorcycle/dp/B0BLGNRQFG/ref=sr_1_3_sspa?crid=ZP7N87343M9S&keywords=compression%2Btester&qid=1695092454&sprefix=compression%2Bt%2Caps%2C123&sr=8-3-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

Thanks! I'll have to give this a try.