96 GTX - Buy or not to buy?

[mejim707]

I have an opportunity to purchase a 96 Seadoo GTX. It's been sitting since 2015 in a garage.

Condition:
PROS

• Very clean inside and out.
• Decals are in mint condition.
• Seats are perfect (Only fading is a little on the top of the wheel)
• All electronics work.
• Turns over strong. Didn't attempt to start - See cons
• New carbon bearing
• Pump is perfect with new wear ring
• Engine is in factory paint, with no chipping
• Carbs are in factory paint with no chipping
• Plugs look to be in perfect condition with no signs of rich or lean running conditions.

CONS

• Compression: MAG 100PSI, PTO 130PSI - This will require a top end rebuild @ ~$530 from SBT
• Intermittent starter issue. Very likely the solenoid or may require starter rebuild. Easy job.
• All fuel lines are original factor gray. All will require replacement and will cost about $35.
• Will require carb rebuilds due to the gray lines.
• Trailer tires are no good. About $100 for 2 new ones.
• Needs new battery. About $120.

I'll need to put in about $800 in parts. So I'll be into the machine at about $1300. Based on everything I looked at and the condition, the GTX would be in near perfect condition once I'm done. I can do the work over the winter a little at a time.

Lastly, could a Rotax 787 sitting for 8+ years have sticking rings resulting in the MAG compression being low? Before even attempting to turn it over I dripped some 2cycle oil down the carbs and directly into the spark plug holes to give it some lube.

I ran the compression test with the opposite plug in and out, as well as at WOT and not. In each test the compression was exactly the same on both cylinders. No difference. I did not attempt to start it due to the gray fuel lines and potential of clogging the carbs.

So, based on the above, is $500 for this GTX a fair asking price? I offered $300 but the seller came down to $500 and seems very firm here.

If I did restore this, and it's in excellent running condition, is there any value left in the SKI if it's in near perfect condition? I don't indent on selling, but I want to be sure I still have some value in the machine.

What are your thoughts?

 

[tobytd]

$1300 …GOOD (to go) ski and trailer?
Seen the prices people are asking lately?
If I was in the market for one I’d go for it.

 

[burtshaver2021]

I have an opportunity to purchase a 96 Seadoo GTX. It's been sitting since 2015 in a garage.

Condition:
PROS

• Very clean inside and out.
• Decals are in mint condition.
• Seats are perfect (Only fading is a little on the top of the wheel)
• All electronics work.
• Turns over strong. Didn't attempt to start - See cons
• New carbon bearing
• Pump is perfect with new wear ring
• Engine is in factory paint, with no chipping
• Carbs are in factory paint with no chipping
• Plugs look to be in perfect condition with no signs of rich or lean running conditions.

CONS

• Compression: MAG 100PSI, PTO 130PSI - This will require a top end rebuild @ ~$530 from SBT
• Intermittent starter issue. Very likely the solenoid or may require starter rebuild. Easy job.
• All fuel lines are original factor gray. All will require replacement and will cost about $35.
• Will require carb rebuilds due to the gray lines.
• Trailer tires are no good. About $100 for 2 new ones.
• Needs new battery. About $120.

I'll need to put in about $800 in parts. So I'll be into the machine at about $1300. Based on everything I looked at and the condition, the GTX would be in near perfect condition once I'm done. I can do the work over the winter a little at a time.

Lastly, could a Rotax 787 sitting for 8+ years have sticking rings resulting in the MAG compression being low? Before even attempting to turn it over I dripped some 2cycle oil down the carbs and directly into the spark plug holes to give it some lube.

I ran the compression test with the opposite plug in and out, as well as at WOT and not. In each test the compression was exactly the same on both cylinders. No difference. I did not attempt to start it due to the gray fuel lines and potential of clogging the carbs.

So, based on the above, is $500 for this GTX a fair asking price? I offered $300 but the seller came down to $500 and seems very firm here.

If I did restore this, and it's in excellent running condition, is there any value left in the SKI if it's in near perfect condition? I don't indent on selling, but I want to be sure I still have some value in the machine.

What are your thoughts?

500.00 for the ski and trailer? I would say that’s a good price, I think your in Canada? In Ontario that machine would be listed for 2500.00 to 4000.00 in good working order and it sounds like this one is cosmetically in better shape than most

 

[etemplet]

You're always buying a Pig in a Poke with these skis but it's worth $500 for certain. I spend that on skis with locked up engines. I keep these two for my wife and I because the match and I surely don't need more skis than this to have a good time. They handle GREAT and have good power.

 

[mejim707]

$1300 …GOOD (to go) ski and trailer?
Seen the prices people are asking lately?
If I was in the market for one I’d go for it.

Hi, thanks for the reply, yes it's the SKI with trailer. Both are in great condition other than the issue with the bad compression on the MAG.

 

[mejim707]

500.00 for the ski and trailer? I would say that’s a good price, I think your in Canada? In Ontario that machine would be listed for 2500.00 to 4000.00 in good working order and it sounds like this one is cosmetically in better shape than most

Yes, it comes with trailer. So these still have skin in the game once it's in proper working order? I live in the US, North East.

It's hard to find consistent details on how much I could turn it around for.

 

[mejim707]

You're always buying a Pig in a Poke with these skis but it's worth $500 for certain. I spend that on skis with locked up engines. I keep these two for my wife and I because the match and I surely don't need more skis than this to have a good time. They handle GREAT and have good power.

View attachment 64321

Hey man! Yeah, this one looks identical to the one on the right in this picture. It has the green bottom. And it looks just as clean too.

So based on this, I'm thinking about proceeding then. It seems the consensus is that the deal is good. I've just never done a top end on one of these and based on the lack of space it looks like I may need to pull the engine out lol I just finished doing all that with my boat so if I get this I may have to do the same.

Is it possible to do a top end rebuild while the engine is still in the SKI? And one a scale of 1-10 what's the difficulty if the engine is left in the SKI?

 

[etemplet]

You don't have to pull the engine to do the top end. Pull the head and take a look at the cylinders and piston tops.

To answer your question it isn't worth pulling the engine to do the top end alone. I've pulled the mag flywheel with the engine in the ski.

 

[mejim707]

You don't have to pull the engine to do the top end. Pull the head and take a look at the cylinders and piston tops.

To answer your question it isn't worth pulling the engine to do the top end alone. I've pulled the mag flywheel with the engine in the ski.

Awesome then this is sounding very promising. I'll reach out and tell him he's got a deal lol

 

[burtshaver2021]

Yes, it comes with trailer. So these still have skin in the game once it's in proper working order? I live in the US, North East.

It's hard to find consistent details on how much I could turn it around for.

I never buy a machine to turn over for a profit, I only do it because I want the machine and enjoy learning to work on them, I can always sell them for more than I have into them but if I were to figure in the time that I have invested I would normally be further ahead just working those hours.

 

[etemplet]

I enjoy doing complete restorations on the skis. I don't believe they will be long term reliable any other way. I find too much wrong with them in the process. People have no idea how much work is involved.

 

[mejim707]

If the top end rebuild isn't a major issue in the boat, then this should come together without much trouble then.

I told the guy he has a deal. I'll be picking it up soon and ordering the top end kit from SBT.

 

[burtshaver2021]

If the top end rebuild isn't a major issue in the boat, then this should come together without much trouble then.

I told the guy he has a deal. I'll be picking it up soon and ordering the top end kit from SBT.

What kind of pistons does SBT sell? I’ve read a few times on here that WSM is good, Pro X better and OEM best

 

[mejim707]

What kind of pistons does SBT sell? I’ve read a few times on here that WSM is good, Pro X better and OEM best

They sell and entire top end rebuild kit which comes with the jugs, pistons, rings and seals.
SBT Cylinder Exchange Top End Kit for Sea-Doo 787/800 XP/ GSX/ GTX/ SPX/ Challenger/1800

One question, I'm reading things where people say if you do a top end on an old motor the bottom end will fail. Then the suggestion being to just do rings. This motor does look original since the original gray fuel lines are still on it. But the motor looks very clean with no signs of a lot of use.

It's hard to say what the best approach would be since I have no way of seeing the internals of the bottom end. I'm planning on pulling the head when I get it, and maybe if the cylinders are ok I'll just do the rings.

 

[burtshaver2021]

They sell and entire top end rebuild kit which comes with the jugs, pistons, rings and seals.
SBT Cylinder Exchange Top End Kit for Sea-Doo 787/800 XP/ GSX/ GTX/ SPX/ Challenger/1800

One question, I'm reading things where people say if you do a top end on an old motor the bottom end will fail. Then the suggestion being to just do rings. This motor does look original since the original gray fuel lines are still on it. But the motor looks very clean with no signs of a lot of use.

It's hard to say what the best approach would be since I have no way of seeing the internals of the bottom end. I'm planning on pulling the head when I get it, and maybe if the cylinders are ok I'll just do the rings.

From what I’ve read it’s mainly the 951’s where it’s recommended to not only do a top end. I think all the other 2 stroke engines would be fine with only a new top end as long as the crank sounds and feels ok. I’ve done a couple tip ends on snowmobiles and I just rotate the crank with the connecting rods, if it’s smooth with no play which it was I went ahead and did the top and all had been well so far. Does that machine show the hours? It’s usually not recommended to replace only the rings but if the bores where within spec you could just do new pistons and rings, you would have to mesure them using dial bore gauge and caliper.

 

[burtshaver2021]

One of my biggest worries would be why that mag side cylinder was so much lower in compression? Might be a good idea to do a leak down test on the motor before taking the cylinders off just in case it was running lean from a leaking oil seal. Could be from a number of other causes but hate to do a new top and have that money wasted

 

[mejim707]

One of my biggest worries would be why that mag side cylinder was so much lower in compression? Might be a good idea to do a leak down test on the motor before taking the cylinders off just in case it was running lean from a leaking oil seal. Could be from a number of other causes but hate to do a new top and have that money wasted

I don't see any leaking oil in the hull. But the SKI does have the original gray fuel lines which will break down and clog the carb starving the motor of fuel. I'll be replacing all of those and rebuilding the carbs.


I've never done a leak test so I'll need to look into how to do that.

 

[burtshaver2021]

I don't see any leaking oil in the hull. But the SKI does have the original gray fuel lines which will break down and clog the carb starving the motor of fuel. I'll be replacing all of those and rebuilding the carbs.


I've never done a leak test so I'll need to look into how to do that.

I agree that it could have been from fuel starvation, you could go ahead and replace everything and hope for the best but if it did end up being a leaking crank seal you would then have to pull the engine. You should be able to perform the leak down test with the motor still in the hull by taking the exhaust and carbs off then sandwiching an old tire inner tube between carbs and intake and between tuned pipe and exhaust manifold, then pressurize to 6 pounds through the pulse fitting on the crank. Should hold that 6 pounds for 8 minutes. You can also test the rotary valve cavity by pressurizing through the RV fitting and blocking the return line beneath the exhaust. This will tell you if your inner crank seals are leaking which if they are could trick you when your doing the leak down.

 

[Grim]

Sounds like a good deal, I would say though, as some of the others were eluding too, make sure you know or find out what caused the low compression issue. If you don't fix that, the problem will repeat itself. It could be just worn out, how many hrs on it? Or it was a carb issue? Do your best to understand it and watch it closely when you put the top end together. good luck.

 

[etemplet]

They sell and entire top end rebuild kit which comes with the jugs, pistons, rings and seals.
SBT Cylinder Exchange Top End Kit for Sea-Doo 787/800 XP/ GSX/ GTX/ SPX/ Challenger/1800

One question, I'm reading things where people say if you do a top end on an old motor the bottom end will fail. Then the suggestion being to just do rings. This motor does look original since the original gray fuel lines are still on it. But the motor looks very clean with no signs of a lot of use.

It's hard to say what the best approach would be since I have no way of seeing the internals of the bottom end. I'm planning on pulling the head when I get it, and maybe if the cylinders are ok I'll just do the rings.

You're gonna get lots of opinions. Up to you to make a decision you are comfortable with.

Take your time and enjoy the journey.

 

[mejim707]

I'm leaning toward pulling the engine out and doing the work on a bench.

I have full genuine mikuni carb rebuild kits on the way which include the needle and seats.

I'll pull the head and review the pistons and cylinders. But, is it possible that the rings on the MAG could have been just stuck or gummed up? This ski has not run in 8 years and when I ran the compression test it was done so cold.

I wonder if perhaps I should first replace the fuel lines and rebuild the carbs, then start it and letting it run for a few seconds then conduct the compression test warm.

Thoughts?

 

[POPPS]

That engine is easy to pull,,,,so much easier with the motor on the bench,,,,just scribe around the top bolts holding the motor to the bracket,,,take some closeup pics,,,and you won‘ t need an alignment tool to reinstall the motor,,,don’t remove the bottom brackets going into the hull,,,,

 

[mejim707]

That engine is easy to pull,,,,so much easier with the motor on the bench,,,,just scribe around the top bolts holding the motor to the bracket,,,take some closeup pics,,,and you won‘ t need an alignment tool to reinstall the motor,,,don’t remove the bottom brackets going into the hull,,,,

Thanks for confirming Popps. I do actually have the alignment tool. I purchased it form SBT when I replaced the challenger motor.

But yeah, if I end up having to rebuild the top end, I'd much rather it be on the bench. I don't want to lose any of the needles into the case.

It seems I just remove the pump, drive shaft / carbon bearing, unbolt and move exhaust out of the way, unbolt 3 upper mount bolts then just disconnect cables and hoses. It seems pretty much exactly like the challenger. I could likely have the engine out and on the bench in 1 hour.

 

[POPPS]

Why struggle?

 

[spinyard]

Those older 787 engines have a labyrinth seal on the crankshaft that keeps the oil from seeping into the cylinders from the rotary valve shaft, they almost all leak from age, resulting in the cylinder filling up with oil when sitting in the garage when not being used. Plan on swapping the crank too while your in there and make sure you rebuild the carbs 100% correctly, clean the entire fuel system out, buy a new fuel selector valve and you should have a good running trouble free ski.