New to me Seadoo

[Ronnie]

I bought myself a late Xmas present. Paid $850 for a 1999 Seadoo XP limited with a 135 hp 951 cc two stroke engine and trailer. The compression is low in one of the two cylinders so I know it needs some work. Once I determine how much in money and time it will take I will decide whether to repair the PWC or sell it as is. If I keep it I will replace the fuel lines, and fuel switch, re-cover the seat and replace the mats with hydro turf as well as add a keel and splash guard. Here are a few pics.

 

[4x15mph]

Ronnie, looks good. Did the $895 include a trailer? That sounds like a steel and I guess you will know more once you rip through it. Looking forward to seeing the progress

 

[Ronnie]

@4x15mph , thanks, I feel like I got a good deal and should'nt take a loss on the bundle should I decide to resell it as is. The trailer was included in the $850 bundled price (allocated $750 for the pwc and $100 for the trailer). However, the trailer is not matched to the pwc in that the trailer is more than a few feet longer than it needs to be and looks like it is meant for a small fishing boat, possibly the LRV (I.e., a 4 person 13' long pwc by Seadoo) or maybe even two smaller PWCs sitting one in front of the other. Here is a pic of the ski on the trailer.

 

[Ronnie]

Progress report 1:
- added marine stabil to the fuel (the tank is full of 92 octane)
- cleaned out the trailer locker which had a gallon of Seadoo 2 stroke oil along with two vests and the pwc cover in it
- removed a mass of line from the drive shaft with dremel, took at least an hour

- discovered that the pwc has an aftermarket top loader intake grate by worxs

- the impeller looks good and maybe aftermarket since it is polished

- noted a visible hole in one of the small lines attached to the exhaust

- noted one of the head bolts had high temp silicone on it, as it turns out this bolt is damaged / partially stripped

- pulled the head expecting to see the top of the first piston and the dome of the head above it spattered with metal fragments (from a failed piston ring or worse crank bearing) but both look good as does the side wall of the cylinder. The low compression (first cylinder is at the bottom of the pics)



- as expected, the tops of the two pistons, the domes in the head and the spark plugs are different in color (rich v lean). The dome in the head over the first cylinder with the low compression is the one in the top (the black one) in the pic.

Since the piston, head and cylinder look good I'm not sure what is causing low compression in this first / front cylinder (60 psi v 120 psi in the second / back cylinder). Hopefully, it just a gasket failure and not a hole in the block. Any ideas/thoughts?

Next steps
- reinstall the battery which has been charging overnight to see if the spark plugs are firing and the variable trim system (VTS) is working
- prep the pwc (loosely put the head back on), cover it and move it and the trailer out of my garage
- take the bundle to a pwc shop that I trust, The Ski Clinic. The inspection/ diagnostic fee is $120ish for an hour of labor but they will be able to identify the problem(s) faster than I. If it is something that can be fixed for $850 or less I will likely have them do it, if the repair cost is higher I will put the bundle up for sale.
- If I keep it I will sell or trade the trailer for a shorter one, replace the original plastic mats with hydro turf and add a splash and keel guard, I will also replace the wear ring if the ski clinic recommends it.

 

[4x15mph]

@Ronnie, the driveshaft and wrapped ski rope may impact the ability to turn the pistons freely but I would expect a lower compression in both cylinders then. Either way, you may want to check the compression if the rope was in fact holding the engine shaft from spinning freely.

 

[OCMD]

Ahhhh the pleasures of a 2 stroke!

 

[Ronnie]

Thanks for the advise @4x15mph, I checked the compression again after I removed the rope and the front one is still off by a lot compared the rear. Next stop the pwc shop.

 

[Ronnie]

Got a call from the shop today, turns out the thrust bearing on the front of the crank has failed so the crank needs to be rebuilt or replaced. I estimate the parts alone will be over $1,100. I will be able to quickly make a fix or sell decision once the formal quotes (rebuild or replace the entire engine) come in.

 

[Cobra Jet Steering LLC]

I noticed the plastic cone is missing on the front of the impellor. You will also need to resurface the heads when you rebuild the engine, you can get a rebuilt crank from S B T and all the other parts you need, just pull out the engine and do it on a bench, then reinstall the engine, be sure the rave valves are also matched to the cylinders otherwise that can snag the rings and check that they are in good working order also check the reeds that model does not use a rotary valve like the other 2 stroke sea doo engines do and inspect the motor mounts and the splines in the P T O at the rear of the engine as well as the driveshaft carrier bearing and seals.

 

[biffdotorg]

Good tips there! Get that animal running, they are a blast to ride solo, almost nearly impossible with a passenger. That is solo riding, wave jumping gem! You are not out anything if you get it running.

Good luck!

 

[4x15mph]

Got to fix her and that is the beauty of a 2-stroke. What does a rebuilt, replacement engine cost for that? $1000? Drop in and replace project for you and your son. I think that will be the only real option since having a place take care of this is going to cost at least 2x (parts + labor). You got this

 

[Ronnie]

I forgot to mention that before I took the ski to the shop I removed the cylinders (and a lot of other parts) to get a better look at the pistons. As suspected the front/mag side piston rings where bound / seized within the piston ring grooves on one side of the piston so that's what caused the poor compression and the rear/pto side piston showed early signs of seizing. When my mechanic took a quick look he confirmed what I saw and noticed that the top end had been rebuilt already with parts he and guys on greenhulk don't recommend. He also suspects the carbs may not have been rebuilt / set up correctly.

Thanks for the advice guys. I'm still waiting on quotes from my mechanic and was tempted to do the work at first initially but always intended to have my mechanic inspect and fine tune it before I launch it for the first time. Now that it's already at the shop 60 miles away I will just have him do the rebuild or replacement if I go that route.

So far I'm into this $850 for the ski and trailer, plus $120 for diagnostics. I know I will have to spend another $100 to transfer title on the ski and trailer. I won't buy any mods (new turf, seat cover, keel guard, primer kit, finger throttle) unless or until I get the engine issues fixed.

A top end rebuild from a third party is $450 including Pistons, rings, gaskets, resurfacing the cylinders and head as well modifying the rave valves.

A rebuilt crank is anywhere from $500 to $1,000 so average $750.

A rebuilt engine (not SBT) but my engine rebuilt with the brand parts I choose is $1,200 and comes with a two to three year warranty.

My mechanic has done some magic for me in the past so I'm interested in his opinion and recommendation.

As for making this a father son project it will take some time for my boy to warm up to that since he thinks this may be a replacement to the ski we already worked on together. Truth be told I am thinking about selling his ski if I get this one going and built up. This is our third ski and we only take two to the water at any given time. I'm sure my wife doesn't want me to sell the fx cruiser and I'd be fool to do so since its been such a great ride (I.e. Four stoke reliability, plenty of power, three seats and lots of storage). Overall not a bad problem to have.

More to come.

 

[Ronnie]

Last update on this:

The shop's recommendation is that I either rebuild the engine (top and bottom as they found that the thrust bearing on the front connecting rod/crank Is shot) or replace it with a remanufacutered one. The quotes came back at $2,200 and $2,400, respectively this is before any carb work / tuning that may be needed. So I sold the pwc and trailer for $750 on Sunday. They guy was more interested In The trailer and posted the Seadoo up for sale already, here is link to his ad. https://sacramento.craigslist.org/boa/5991973337.html .

I still want a Seadoo XP (if I buy another it will be my third, the engine blew on the first one I had on the second session after I got it running). I've seen several ads for '96/'97 XPs with 800 cc motors and '98/'01 XPs with the more complex 951 cc motors for between $1,000 and 1,200 some with and others without a trailer but they are in Scal so my search will have to wait until at least the end of this month when I should have some time to drive down there.

 

[Cobra Jet Steering LLC]

Just my opinion on the 951 STAY AWAY FROM THEM. The way they set up the engine in the hull with the air intake system being so low they like to ingest water and hatch and NEVER buy any D I engine EVER.
If you get the 787 carb engine you will usually get very good service out of them providing someone did not do a half baked rebuild on it. Oh and move the flush fitting as far away from the air box as possible. Expensive lesson learned as I lost one to a leak in that fitting blasting water directly into the air intake system.

 

[Ronnie]

@Cobra Jet Steering LLC , Jeff, thanks for the advice. I was leaning back toward the 800/787 cc engines anyway since I have had a few of them but the extra power of the 951s (110 v 135) is tempting. At the same time the fact that the used prices of each are close to the same makes me really reluctant to buy another 951 even if it's operating well at the time.

 

[veedubtek]

Picked this up for $100 the other day. Never messed with an old one like this. Completely in pieces, but was disassembled neatly and methodically. Kinda excited to mess around with it. If I can get it going, just gonna leave it as a "loaner" type ski at my campsite. Speaking of, the neighbor at my new campsite has an old yellow XP that looks like it hasn't moved in years, and a couple stand ups. Might try to snag those if I ever see him there.

 

[Thom]

1995 GTX? I have a couple of them, they're pretty solid old skis.

 

[MattFX4]

I've had three of these XP's. A 2000, a 2003 xp di, and a 2004 xp di. Never had a problem out of any of them. I beat them to death to. Man were they fun to ride, and the DI's sipped fuel compared to the carb version.

 

[Ron@Scarab]

Famous last words of a 2-stroke owner,....it ran Great,...and then all of a sudden. Both of your cylinders clearly ingested some water a time or two. I love the orange rtv around that nut/stud on the head! Somebody probably put that on there to keep the water from leaking out since they left the o-ring out on the stud,..or it went bad. That ski possibly overheated,...noticed the melted hose on your exhaust for your water by-pass (check the 90 degree fitting to the cylinder head since they get clogged a lot from shallow water use). The 951 motor makes power, but it don't add water to it, lol! The Worx intake grate works great on the XP,....get a new seal for that impeller. Replace the wear ring while you're at it if you choose to fix her up. Good luck!

 

[Ronnie]

Thanks for the advice but I sold that ski in late Jan. Or early Feb., there was just too much to do to get it running. The Sephora I took it to said the cylinders had already been bored to the max so it would only take one brand of piston (the only company that makes them that big), the brand and forged piston did not have a good reputation. I'm looking at another one that is running but roughly with a trailer for $600 but may pass on it for an older version with a more reliable 800 cc motor.