2001 Mercury M2 210 Jet Drive Piston trouble

[Sam Fisher]

Hey guys,

I recently bought a 2001 sea doo sportster with the above engine. Anyways, the piston failed the other day for the 3rd time in 1 year. I just found out it had broke two times prior today. It's in the same cylinder, it has a thermostat, and it wasn't overheating. The mechanic that has worked on it in the past said it was the piston/rings that need to be replaced. I don't want to replace them without knowing why the piston keeps failing. Any suggestions on what may be causing this are appreciated! Thx

 

[Djs]

Have you and pictures and is there any damage to the cylinder wall/bore?

 

[Sam Fisher]

I don't have any pictures of what it looks like after this 3rd time, but I was able to track down what has been done over the past year and a half...unfortunately after I bought it. It's cylinder #4 that is having all the issues

 

[Djs]

This looks like a reoccurring issue and a picture would help with diagnosis, etc has overheating caused the piston to seize and damage the cylinder, that said overheating would possibly damage other cylinders also. Other issues could be due to detonation/fuel, oil or mechanical failure.

 

[Sam Fisher]

Thx, it has a thermostat attached to that particular piston #4, and it was not overheating per the thermostat

 

[Dr Honda]

It's not overheating... it's going lean. As above... if it was overheating, you would eat other pistons too. But, a plugged up carb, or open bleed hose... or.... a broken reed.... and that cyl goes lean. In turn... it eats itself.

Pictures of the piston are mandatory to know for sure.

 

[Sam Fisher]

It's not overheating... it's going lean. As above... if it was overheating, you would eat other pistons too. But, a plugged up carb, or open bleed hose... or.... a broken reed.... and that cyl goes lean. In turn... it eats itself.

Pictures of the piston are mandatory to know for sure.

Thanks, I will get the pics!

 

[Sam Fisher]

It's not overheating... it's going lean. As above... if it was overheating, you would eat other pistons too. But, a plugged up carb, or open bleed hose... or.... a broken reed.... and that cyl goes lean. In turn... it eats itself.

Pictures of the piston are mandatory to know for sure.

Here is a pic of the piston...I’m going to sell it, any idea what to ask for it?

 

[Djs]

Look like it has run lean eaten the piston and possibly a ring has broken and particles are lodged in the piston crown. Is the cylinder damaged?

 

[Sam Fisher]

It's not overheating... it's going lean. As above... if it was overheating, you would eat other pistons too. But, a plugged up carb, or open bleed hose... or.... a broken reed.... and that cyl goes lean. In turn... it eats itself.

Pictures of the piston are mandatory to know for sure.

Hi Dr. Honda,

Here are 2 pics of the piston. My mechanic replaced block, pistons, etc...but I’m not sure if he found the cause, can you give me any indication what might be causing this? Same cylinder, 3 times. He also removed the oil injection if that helps.