Low compression pto 96 GTX

[Orbitalatx]

Ski was hard starting in the water pulled it out and starts good on trailer for two seconds. Went back home tested compression and got mag side 150 and pto 125. Pulled engine and found some scoring on these. The gaskets seems flat and old. Are they shot? Should I go ahead and rebuild the lower end as well? Any thoughts or help would be appreciated. What's my next step should I continue testing things or just go ahead and rip it all apart and plan for a rebuild?
Mag side: 150 compression


Pto side: 125 compression


Jug pto:

Jug mag:

 

[Orbitalatx]

Also on pto side piston you can see a four leaf pattern. What could that be from?

 

[mikidymac]

Looks like water ingestion or just rust from condensation.

With that kind of rust staining I would do a full rebuild if it was mine.

 

[Orbitalatx]

I had a feeling you was gonna say that Mac. Already started planning for it. Yes ski took on water last season because of a carbon ring that busted I was a mile from shore and engine died suddenly omw back. Started sinking and got a tow from another boat. Electricals fried all the way through. Boat full of water over halfway by the time I got to the dock.

 

[Orbitalatx]

Is this part reusable with the putting on the right?

 

[mikidymac]

Yea, I have seen worse. I would just file down any high spots.

 

[Orbitalatx]

Ok look at the jugs real close. The left one the part number pulls a 1999 787 but the right one is correct 1996 787. Should I be concerned? The thickness of the cylinder sleeve and taper is completely different.

 

[Orbitalatx]

 

[Orbitalatx]

Replaced cylinder with one off ebay for a 96 gtx. Did the pistons and rings. Rectifier needed replaced also. Water control valve fixed. Carbs low jets 1 turn and high 0 pto high 1/2 and she rips. Glad to finally get this thing on the water again after 2 years. Thanks all for the help.