91 XP 580 yellow no compression

[dz0k52]

I just acquired (free) and 91 Seadoo XP. I was told it ran but one cylinder was "missing". A quick compression test shows no compression in the front cylinder. I guess I want to know is this a common problem? Do I have to pull the head off or is there something else to check first? ( I can see piston going up and down and can't see damage through spark plug hole.) Should I pull head off no matter what?
Also, I keep hearing of folks who get rid of the oil injection and mix their oil. I would hate to do that but is it a must? Is there a way to check the oil injection system? Is this machine worth all the fixing? The hull is okay but I don't want to be fixing this all the time.
Any advice would help....also a link to a repair manual would be awesome.
Thanks

 

[Dr Honda]

Welcome.

1) nope... it's not a "Common" problem... but it's a 20 year old 2-stroke. It's probably time for a rebuild. BUT... pop the head off, and tell us what you see. I bet the edge by the exhaust will be melted through.

2) I like the oil injection. Don't remove it unless there is a problem with it

3) Yes, you can check it. You can remove the pump, and spin it with a drill to check it's output. BUT, since it's an old ski, I would just do a full service on it (new hoses, and filter) then when you bleed the system... you will get a visual check on if it's pumping.

4) It's up to you if it's worth fixing. The old hulls are fun to ride, and they are very light. BUT, the old skis aren't worth much, even in good running order... so a new engine will probably be more that you could sell the ski for. Not to mention, once you start the rebuild, you may find other problems.

I personally have a very nice, and rebuilt 91 Si... but I don't have much $$$ into it.

Good luck

 

[Bills86e]

I put a 720 in my '93 SP. It is the one of the most fun of all my toys! If you are fixing to pass it down, Upgrade!

 

[dz0k52]

You were right Dr. Honda. There is a chunk out of the front piston and dings all over the piston and head. How far should I go. Should I pull the engine out and look at the rotary valve. Do I need to open up the case? Not sure what caused the failure but there was sand on the right side at the bottom of the water jacket. It looks like there is no where for that to go anyway. You can also see in my last picture, there was a build up to the point of being plugged in the bottom of that jacket. Also I found a site where I was able to download a shop manual for a 92. I think its the same?? ( I hope the link to my pics works??) ( i just uploaded pictures into my album.....cool site)

 

[dz0k52]

Okay I dug deeper and found the jet drive housing was also cracked (by doing air test ). I located and bought a used motor and housing on craigslist for $400. The guy ran the motor (with a shot of starter fluid and wd40....not the best choice) and I did a compression test and got 120 and 115psi. This was supposed to be from a 1992 SP. It has only single carb and when I got it home I realized that the water jacket around the exhaust manifold was smaller.
1) Can I just swap out the intake and carbs and put my twin carbs on this unit?
2) Can I put my exhaust manifold on (with larger water jacket)
3) Is it possible this is not from a 92 SP?????AKA did I get f%$#*%

 

[Bills86e]

You'd be lookin at $500 for a shortblock from SBT: http://www.shopsbt.com/seadoo-jet-ski-engine-standard/40-101.html
Another $100 for carb, $100 for a used pump. IMO Plus installation labor, plus fuel delivery rebuild. Guessing your electronics are good?

Its a wore out engine Ya bought, sorry dude. White or yellow engine yah?

 

[dz0k52]

That sucks. At this point I just want to get it running. Can I do the carb/manifold swap ?

 

[Dr Honda]

That sucks. At this point I just want to get it running. Can I do the carb/manifold swap ?

Yes you can... but the engine with 120/115 psi is shot. It's not going to run once it's in the water. (sorry to have to say that)

 

[dz0k52]

What is the low end of compression which would still run okay?? Could a wore rotary valve cause that or am I for sure into the heads, pistons, rings??
At this point I think I have a couple of choices at this point, fix one of the engines (original yellow or used yellow(which was painted white??) or part everything out and cut my losses. It is starting to feel like this old 91 is becoming a pit and not worth time,effort or money.

 

[Dr Honda]

Up on my original post.... they aren't worth much... so yes, it could become a pit quickly.


Anyway... the low end of "USABLE" compression is 135 psi. 145 to 150 psi is a fresh yellow engine. Once you get down to 130... the engine will degrade quickly since hot blow-by gases overheat the lower half, and displace the oil.


Assuming the engine you bought isn't totally roasted yet... I would do a quick and sloppy top end on it. Pull the head and the jugs, and figure out what size pistons it has. As long as the cyl walls aren't ripped up, just replace the rings, and put it back together. That should get you a season or two of use.


Sorry, but I'm not quite sure what you are asking about with the rotary valve.

 

[estoarn]

Looks like I have one too

I also got a 91 XP for basically free, I bought a trailer for my other Seadoo and the 91 came with it. They said it ran this summer and then died in the lake. They said the compression was 30. I checked the compression (both plugs out, WOT) and had 60 in the rear and 0 in the front. I've cleaned up the outside and de-greased the engine compartment, it doesn't look too bad but I realize it's a 19 yr old machine that I know basically nothing about how it's been maintained.

Would like to rebuild the top end over the winter as a project to get it running, but don't really want to spend $300 - $500 and have nothing to show for it but new parts.

Should I pull the head cover off and give it a visual? I like the feedback and help you guys gave to dzok52

There's a repair shop about 30 minutes away, they could do an assessment for $70/hr, 2-3 hours is what they were thinking. That would give me a shopping list and a bill for 150 - 200 bucks.

Thoughts?

 

[estoarn]

How to winterize if it doesn't run?

One other question (I'm sure there will be many more). What do I need to do for winterization if the engine doesn't run? I have the Seadoo Shop Manual, and it seems to be telling me to check the drain line, stabilize the fuel, then flush the system. The catch is that my engine doesn't run so I'm not sure if I should just manually drain the lines or do the flush procedure while cranking the engine? I am not sure I have the flush tee installed or not. Then while running it says to lube the engine for a minute shutting off the fuel at 30 sec, then shutting off the water and then the engine.

So I'm just looking for the safe way to go so I can get the machine through the winter while I rebuild the top half (assuming that's the way I go).

Thanks!!

 

[Bills86e]

Remove the head and the cylinders. You'll have all winter to think & ask any questions, you'll see hat you are up against and cost. Later, the entire fuel system will need drained cleaned ect. You'll learn AND save! To start, you need a Metric socket set.
You should read the SHOP MANUAL cover to cover.

Bill

 

[estoarn]

Sounds good, so just to confirm...

Thanks Bill, that's what I was hoping to hear.

I have been reading the manual a bit. Removing the cylinder head basically takes care of the water in the jacket, doesn't it? So for winterizing, all I have to do is make sure the water lines are drained? I can find those with the diagrams in the shop manual.

Do I leave the bottom half in the craft and just pull the top?

Thanks
Arnie

 

[Bills86e]

Unbolt the tuned pipe from exhaust manifold top, loosen small end of cone, remove battery-put on trick to save, pull back on shoe tab to release the grey box from floor shoe and pull it around to where battery was, now you can pull pipe up off ex-bolt and forward out of the cone's hose coupler and find the position pipe will pass (its tight) between exhaust manifold and the compartment, to remove from the ski.
next remove the manifold bolts as it holds cylinders parallel. remove the manifold's outer drain line. Now you're ready to remove other side of engine, airbox, flame arrestor & plate, water exit line. Now the head, undercover plate, and four bolts down inside the cooling tower next to
the cylinder. Tap cylinders with a wood or rubber block to loosen. With piston at top, pull cylinder up slowly so as to put a rag completely around the connecting rod so as to catch and metal before it can fall into the lower case. I use also a strong earth magnet on the rod above cloth as I pull cylinder off the piston. Hand turn other piston to top and repete above cylinder removal.
You may just find scored pistons. Now you examine the crank and determine if to pull the engine and do a complete overhaul, or top end only. Use your shop vac in the muffler to either blow or suck out any water if you are storing outside over the cold winter. Lots of great talent on this cite, so post your progress! We may have a trick or two not mentioned in your Shop Manual.

Bills86e

 

[estoarn]

Wow, great direction

Really appreciate the guidance. It might take me a couple of weeks to get that far as I've got trips out of town the next two weekends. I'll post again as soon as I have more information to share.

Thanks!