2002 RXDI Piston and Cylinder Wall Scratches

[Klipsh]

Hi,

I rebuilt a 951 DI in 02 RXDI last summer it ran fine. I discovered i had an exhaust leak so I pulled off the whole exhaust and I just decided to take a look inside the cylinder and I saw the piston was scoured I have since pulled the engine and got it apart ill link the photos. I am a rookie looking for advice as to how I should proceed I think a ball hone is in order first the sleeves are brand new and a machine shop did all the clerances etc. Most of the scratches you can barley feel but I'm concerned as to why there is so much wear the crank feels good. Any help is appreciated greatly as I am 16 years old with a non-mechanically inclined family I'm figuring things out on my own.

 

[mikidymac]

What oil are you using?
Is the oil pump adjusted correctly?

I would lean towards water ingestion. Is the pipe/exhaust manifold leaking? Do you have the rubber intake covers on?

 

[Klipsh]

What oil are you using?
Is the oil pump adjusted correctly?

I would lean towards water ingestion. Is the pipe/exhaust manifold leaking? Do you have the rubber intake covers on?

I am running "AMSOIL HP Marine® 100% Synthetic 2-Stroke Oil"

I am confident the pump was adjusted correctly, I had it on the richer setting for break in.

Yes, I did have the rubber intake covers on. But on afterthought, I know what the issue was my fire extinguisher had come lose from where I had it mounted and started releasing its contents while I was riding it wasn't much but it was a dry extinguisher, and I'm more than confident it caused that excessive wear on the piston skirt. But im not sure if it could have scoured the piston

My question to you is would I need new pistons? I think I could most likely ball hone the cylinders as the scratches are not that bad.

 

[mikidymac]

I would have the cylinders measured for wear and new pistons and rings if it was mine.

All the black dots are not normal on the aluminum either and makes me think water ingestion, very strange.

I would also use Amsoil 2-stroke injector as it is API-TC rated as required by your seadoo, not Amsoil HP Marine that is TCW-3.

 

[Klipsh]

I would have the cylinders measured for wear and new pistons and rings if it was mine.

All the black dots are not normal on the aluminum either and makes me think water ingestion, very strange.

I would also use Amsoil 2-stroke injector as it is API-TC rated as required by your seadoo, not Amsoil HP Marine that is TCW-3.

Thanks for the advice,

The pistons before run time already had that on them. Maybe hard to tell from the photo but they do have those black specs. Sleeves did not have those spots black spec spots of course.

Do you happen to like any pistons in particular and rings?

Ill change the oil, back when I did my research I came across a few sources saying that oil was really good.

 

[mikidymac]

On a DI I prefer OEM pistons because they are hard anodized for the direct fuel injection.
IF I had to go aftermarket I guess I would go Pro-X.

 

[Boyd12]

I think photos make the issues look a little worse than they actually are.
Was the engine run out of the water? If so, how long? If you ran it using a garden hose, did you turn the water on then start the engine?
I would hone it and run it, make sure that there is plenty of oil on initial start-up. Switching to API-TC is a good idea, but I dont think it caused this.
Doing this type of work on this engine at 16 years of age is impressive!

 

[Klipsh]

I think photos make the issues look a little worse than they actually are.
Was the engine run out of the water? If so, how long? If you ran it using a garden hose, did you turn the water on then start the engine?
I would hone it and run it, make sure that there is plenty of oil on initial start-up. Switching to API-TC is a good idea, but I dont think it caused this.
Doing this type of work on this engine at 16 years of age is impressive!

Yes the motor was run out of the water quite a lot but never more than 15 seconds without a hose bib as I was trying to diagnose a charging issue. There was one time my dad shut the ski off while I went to turn the hose off but I started it up after to make sure water didnt sit in the cylinder but it might of been enough. Well, on the cylinder on one side, it completely erased the cross-hatching... I think it wore it out pretty darn good. I made friends with an older guy who's 70 years old and running a machine shop out of his home he's been a machinist all his life and has amazing prices. He is super happy to help me out always and I am taking my cylinders up to him to get them measured and then from there we will pick the best choice. Worst case he bores it .25mm over or whatever. I was also wondering if I need to tear down the bottom end. I don't see there being an issue down there. I will just clean up the bottom and make sure there isn't fine debris left. The crank is still in new condition. Thanks for the kind words!