94 XP compression/lean problem

[Sramsay20]

Hey guys- First time posting, need some expert advice.

I have a 94 xp. Recently while on the water, she died at full throttle. Was unable to get it restarted. Starter was unable to turn.

Once ashore and cooled down, was able to get started. I am concerned engine was running lean and pulled ski from the water.

At home, started looking for cause of lean condition, found a crack/hole in the pulse line, from engine block to carbs.

Checked psi, 150 in piston near front of the ski, 120 at rear

If the hole in the pulse line was the cause of the lean condition, and has been corrected, can this sea doo be driven for the rest of summer?

I know a winter top end rebuild is in order.

If the ski cannot be driven, how do I determine what size top end rebuild kit to order? this engine went through a full rebuild 2 years ago.

thank you for your help!

 

[mikidymac]

Can you run it? Yes but for how long.

With those compression numbers and it locking up the 120 psi cylinder seized from the air leak at the pulse line. It is only a matter of time until it seizes again and more damage happens.

 

[TheGTIjetguy]

The pistons should be marked on the top for standard bore or a number marking for an overbore. Just order what you see and hope you find your cylinders to be reusable when you get in there.
If you don’t have a borescope and can’t see through the spark plug holes, then the cylinder head is coming off.

 

[POPPS]

GT has sound advice...usually on most seizures,,,the next overbore solves the problem,,
,So...we ,,read the current overbore on the piston top,,,we buy the next "overbore" piston and then send the jugs and the new pistons to our trusty auto machine shop,,,they have always been to bore the seized/scored cylinder to accomodate the next size piston,,,(so far),,,of course the new pistons comes with the recommended clearance.,,,
So ,,,,up here in ont canada,,,stoney creek ont,,,,to bore the jug is about $120/per jug...pistons are around $150/per piston,,,,the pistons comes with rings, wrist pins and circlips..we order a complete gasket kit because sometimes all we need for a job are the 2 crankcase oil seals,,,that we did not use on the top end rebuild,,,
End of story,,,and so far,,,no comeback/return/engine failures,,,
In the end it all depended on discovering/having a machine shop that would bore a 2 stroke cylinder,,,and a parts supplier,,,(Winners Circle),in Toronto,,,and they will ship to the US
Wwhats crazy,,,everyone in our racing/pec repair shops...did not want disclose who bored their jugs,,.and where in the hell they got their topend/piston kits from...
And when you think of it,,,thats it...bore the jugs,,.put in the new appropriate "over" piston...as I mentioned...WINNERS CIRCLE...woodbridge ont canada ships...and they have a ton of parts,,,write to them and have them send you their pwc catalogue...and of course they have skidoo parts as well...
Hope this helps many out there...

 

[Sramsay20]

Thanks all.

Im going to open it up and see the condition of the low piston.

POPPS- im in ontario too, ottawa. will check out your shops. Thank you.

 

[Bth9318]

Open it up. The fact that you where able to start it again is a good sign. What needs to be done is all dependent on the amount of damage. Good thing about old seadoo is the iron cylinders. You may just be able to clean things up with some scotch Brite ,hone and new rings. If money is no object do a whole top end. Should be able to have it back in the water in a week. The good thing is you found what caused the lean condition.

 

[Sramsay20]

Open it up. The fact that you where able to start it again is a good sign. What needs to be done is all dependent on the amount of damage. Good thing about old seadoo is the iron cylinders. You may just be able to clean things up with some scotch Brite ,hone and new rings. If money is no object do a whole top end. Should be able to have it back in the water in a week. The good thing is you found what caused the lean condition.

Thanks- what should I be looking for once I have it open? I assume the piston is done, any way to tell if cylinder can be salvaged?

I am really hoping the small hole in pulse line was the cause, I am afraid I will do the piston/rebuild fix and find I have some other problem as well.

Would a small hole in the pulse line be enough to cause this? Also, does it check out that the PTO piston is showing low compression from pulse line problem?

Appreciate any input, have been busy with kids but am dying to get in there and get it sorted out.

 

[Bth9318]

The cylinder will still be good. May need a bore but that's what's good about the seadoo. If it was a plated cylinder it would be junk. Pull the cylinder. Look for deep scratches,did aluminum stick to the cylinder? What does the piston look like? You have to at the very least is pull the head. Your going to need to pull the cylinder to look at the piston. Take pics and post.

 

[Sramsay20]

Hey guys- here are photos- good cylinder, bad cylinder. Good piston, bad piston.

Cylinder doesnt seem too bad- wondering if can be lighly honed with fine grit- and same size piston installed?

bad piston dead

Also- more water in here than expected- should I be concerned?

Bottom end looks real clean- kind of expected this since had a full rebuild a couple years ago

 

[Sramsay20]

image 0 is bad cylinder

 

[TheGTIjetguy]

Your cylinders are bored 0.050 over, which is the max oversize.
It would be ideal to measure the cylinders for taper and out of round wear. You definitely need to drag your fingernail along the cylinder wall though and see if you can feel any scratches. If it feels smooth, then you may be able lightly hone and reuse.

 

[Spider4real]

This is only 0.5mm over. You still have 0.75 and 1.0mm oversize if you need to go larger.

But do as GTI said and measure and feel the cylinder. The cylinder does not look too bad to me. But I'm a newbie at this.

 

[Bth9318]

I guess it all depends on what you want to do and what you can afford. As someone mentioned it's already been bored at least once. Cheap way hone the cylinder, scotch Brite the piston and re-ring. Another option hone,replace piston and rings. Or just redo the top end. I would say depends on what you can afford. There are pwc engine companies that you send them your cylinders and they send you 2 cylinders and pistons ready to install. Uhg I just remembered your in Canada so I don't know if the cylinder exchange is going to work for you. But depending on the engine the exchange is 4-500 and has everything you need to rebuild your top end. One company is sbt I'm sure there are others. I think now I would take the cylinder to a old school machine shop and have them evaluate it. When I say old school I mean one that machining and engine building is all they do and they have been around 40 yrs. Good luck.