Picked up a 1996 GTX, Need Advice

[donc1974]

Hello all. I recently acquired a 1996 GTX with the 787 engine that hasn't run in years and I'm trying to get it back on the water without investing more in it than it's worth. So far I know the PTO cylinder has very low compression...about 30 psi. The mag side is around 120 psi. The belly of the unit has oil in it. I haven't tasted it to see what it is but my guess is it's 2-stroke oil that was supposed to be injected into the engine and this is the cause of the engine failure. I'm considering a top end rebuild kit but I'm worried that it might be a waste of money if the bottom end is also damaged. What's the likelihood that the bottom end is toast as well?

Thanks for the help!
Don.

 

[mikidymac]

50/50 chance. You will not know until you pull it apart.

 

[JC-SUPERJET]

"without investing more in it than it's worth"

Sorry, can't help you there. Asking for the impossible...(half-way joking)

 

[donc1974]

50/50 chance. You will not know until you pull it apart.

Can I get a good idea if the bottom end is shot when I have the top end off of it?

 

[mikidymac]

Can I get a good idea if the bottom end is shot when I have the top end off of it?

Much easier to check all the individual bearings with the crank out.

 

[POPPS]

Just rip it apart,,,and then make determinations.,,at least you will know where you stand,,,

 

[donc1974]

I had some time to take a closer look at things. I found that the oil level sensor was out of the tank and the tank is about 3/4 full. Maybe the oil in the belly was from it splashing around and not an issue with the injection system. I also pulled the cylinder head and the PTO piston and head are banged up. The spark plug insulators were white so I'm guessing a lean condition killed this one. So what's the usual cause of a lean condition on these engines? Carburetion? Bad crank seals? Oil injection?

The cylinders are already bored to 83mm so, based upon what I've learned on this forum, they'd need to be sleeved. I really wanted to get this ski on the water soon but I'm coming to terms with the fact that I should yank the engine and do a complete rebuild or remanufactured.

I didn't see a lot of discussion here on SES engines but what I did see wasn't positive. Has anyone had good experience with them? I'm not far from them in Pennsylvania so that's why I ask.

Thanks again for all the advice! Much appreciated.

Don.

 

[mikidymac]

SES and FullBore are not recommended because they can take years to get your engine back and very poor communication.

IF you want an engine fast SBT is the only option.

 

[Lothsahn]

Usual cause of lean failure is carbs, although leaky seals can cause it as well. When you get a used 2-cycle ski, it's strongly recommended to do the following:

1. Replace all grey fuel lines (these degrade internally, especially if ethanol gas is used. This clogs carbs and causes lean fuel condition) with black lines.
2. Rebuild both carbs with Genuine Mikuni Kits. Do not buy amazon parts--they will not work right. Genuine Mikuni. Carbs can and will cause lean conditions when the rubber degrades or the small fuel filters inside get clogged.
3. Replace fuel selector valve (This can fail internally and cause lean fuel conditions)
4. Check oil injector is hooked up correctly and replace small 3/32" tygon lines if original. These get brittle and fail. Some people bypass the injectors, so you want to make sure they're connected. I don't recommend premix because the oil injectors are actually very reliable, as long as the lines are intact.
5. Replace jet pump gear oil.

 

[Lothsahn]

Here's what I'd do if I were you, given it's been sitting and not running.

1) All of the above

2) Pull oil tank and verify no leaks. The original 1996 GTX fuel tank is a 1-piece tank and generally lasts. The replacement is a 2 piece and it has a seam around the whole tank that generally cracks and starts leaking. Mine had been replaced by a previous owner.

3) Replace top and bottom grommit in the oil tank (same part). One grommit secures the red elbow at the bottom and the other secures the oil gauge that you said was disconnected.

4) Pull jet pump. Verify wear ring, impeller condition, and that the jet pump bearings are in good condition.

5) Rebuild engine or use SBT rebuild ($1500). I personally wouldn't want the bottom-end to fail right after I got done doing all the rest of the work. Make sure you follow the 2-cycle break in procedure for the new engine or the rebuilt top-end.

OR

Give up and get a different ski

 

[Lothsahn]

You said you heard bad things about SBT. Here's the deal with SBT, best I can tell:

1) About 5-10% of their engines are bad, some with obvious problems/cracks that make you really wonder how they didn't notice.

2) They will communicate and deliver on time. They're a large company, stand behind their products, and will do what they say they'll do. All of the other rebuild shops are small individual shops whose estimates are wildly inaccurate and can be hard/impossible to reach.

3) They use their own re-man parts, some of which other rebuilders won't accept. These parts will be reliable in a stock engine, but will fall apart if you use aftermarket modifications (factory pipe, etc) that increase HP. Many people are unhappy about this.

4) They offer a no-questions-asked warranty and will stand behind it.

5) Get the premium engine. It's the same as the standard but has a longer (2 yr) warranty.


I just had an engine failure on my 96 GTX (main crank bearings failed) and had to replace the engine. I've been very happy so far with my SBT engine, and have had no problems.



P.S. If you do this, you're going to spend more than the Sea Doo is worth. That said, once you do all of this stuff, you've got pretty good confidence that everything is going to just work and you'll have a mostly trouble free ski for many years. If you do the labor yourself, it should cost around $2000, including engine.


I personally recommend osdparts.com for all parts--they've been great, ship on time, know their stuff, and use quality parts.

 

[donc1974]

Here's what I'd do if I were you, given it's been sitting and not running.

1) All of the above

2) Pull oil tank and verify no leaks. The original 1996 GTX fuel tank is a 1-piece tank and generally lasts. The replacement is a 2 piece and it has a seam around the whole tank that generally cracks and starts leaking. Mine had been replaced by a previous owner.

3) Replace top and bottom grommit in the oil tank (same part). One grommit secures the red elbow at the bottom and the other secures the oil gauge that you said was disconnected.

4) Pull jet pump. Verify wear ring, impeller condition, and that the jet pump bearings are in good condition.

5) Rebuild engine or use SBT rebuild ($1500). I personally wouldn't want the bottom-end to fail right after I got done doing all the rest of the work. Make sure you follow the 2-cycle break in procedure for the new engine or the rebuilt top-end.

OR

Give up and get a different ski

I have a carb rebuild kit on the way from OSD. All of the fuel lines are black so I think they were replaced at some point but I'm going to replace them again. Will 10 feet be enough? The oil injector lines look original so I'll replace them.

The fuel selector can cause a lean condition? You guys sure are educating me on these skis.

I think I lucked out on the jet pump. The wear ring and impeller look like they are new! The seller also gave me an additional jet pump, steering nozzle, and reverse gate which look pretty good too.

As for the engine, I'm planning on a full rebuild down the road. I'm trying to get this ski on the water and a full rebuild looks like it will take months so I'm going to do a top end rebuild and hope for the best. I know it's a gamble but I think it's my only time sensitive option.

Thanks again,
Don.

 

[donc1974]

You said you heard bad things about SBT. Here's the deal with SBT, best I can tell:

1) About 5-10% of their engines are bad, some with obvious problems/cracks that make you really wonder how they didn't notice.

2) They will communicate and deliver on time. They're a large company, stand behind their products, and will do what they say they'll do. All of the other rebuild shops are small individual shops whose estimates are wildly inaccurate and can be hard/impossible to reach.

3) They use their own re-man parts, some of which other rebuilders won't accept. These parts will be reliable in a stock engine, but will fall apart if you use aftermarket modifications (factory pipe, etc) that increase HP. Many people are unhappy about this.

4) They offer a no-questions-asked warranty and will stand behind it.

5) Get the premium engine. It's the same as the standard but has a longer (2 yr) warranty.


I just had an engine failure on my 96 GTX (main crank bearings failed) and had to replace the engine. I've been very happy so far with my SBT engine, and have had no problems.



P.S. If you do this, you're going to spend more than the Sea Doo is worth. That said, once you do all of this stuff, you've got pretty good confidence that everything is going to just work and you'll have a mostly trouble free ski for many years. If you do the labor yourself, it should cost around $2000, including engine.


I personally recommend osdparts.com for all parts--they've been great, ship on time, know their stuff, and use quality parts.

SES is the company that I have not heard positive things about. It sounds like you and mikidymac are happy with SBT so I'll check them out when I'm ready for my full rebuild.

Thanks,
Don.

 

[Lothsahn]

I have a carb rebuild kit on the way from OSD. All of the fuel lines are black so I think they were replaced at some point but I'm going to replace them again. Will 10 feet be enough? The oil injector lines look original so I'll replace them.

The fuel selector can cause a lean condition? You guys sure are educating me on these skis.

I think I lucked out on the jet pump. The wear ring and impeller look like they are new! The seller also gave me an additional jet pump, steering nozzle, and reverse gate which look pretty good too.

As for the engine, I'm planning on a full rebuild down the road. I'm trying to get this ski on the water and a full rebuild looks like it will take months so I'm going to do a top end rebuild and hope for the best. I know it's a gamble but I think it's my only time sensitive option.

Thanks again,
Don.

If the fuel lines are black, they've been replaced. I wouldn't worry about them. The oil injector lines are like 3/32 tygon or something. You can search this forum for what they are. Also replace the white inline oil filter.

Decreased fuel pressure without a change in air pressure causes a lean fuel condition. The fuel selector can clog or fail lowering fuel pressure. It can also happen if the water separator gets clogged, the fuel filters in the carbs get plugged, or the venturi/small passages in the carb get clogged.

Free impeller is definitely nice! The pump might go bad (especially if you run it in murky/shallow water, but the others should basically last forever. Still make sure you change out the gear oil in the pump bearing and make sure the bearing is in good condition. If the pump bearing fails, it will destroy the entire jet pump hub and likely swamp the ski.

If you've got the money, sbt should be able to get you a fully rebuilt engine quick. You'll need an alignment tool and some know-how to install it, but that might be faster? than doing a top-end rebuild. Then at least you're good to go for 10 years...

Yearly maintenance is the following:
marine stabil in fuel
Pump gear oil change
Oil filter replacement
Clean Rave valves

Like I said, it'll probably cost more than it's worth, but when you're done, it'll be a fun little toy. Loving mine!

 

[donc1974]

Hey all. I just wanted to take a moment to provide an update on my progress. I rolled the dice and just rebuilt the top end of the engine. I rebuilt the carbs with genuine Mikuni parts, replaced the fuel selector valve, replaced fuel and oil filters, replaced all suspect fuel and oil lines and clamps, and rebuilt the rave valves. I'm happy to say that it's back on the water and running great! I was concerned that the reason it went lean and cooked the engine was due to leaky crank seals but I did a plug chop and they are a nice dark brown color.

I bought the ski and trailer for $500 and put another $500-$600 into it so I'm feeling pretty good about my investment right now. Also, I learned a lot and it inspired my son to get his boating certificate. He's loving it so maybe I'll be looking for my next project soon so I have a ski to ride with him.

Thanks for all of your replies offering advice. This forum was a valuable resource during the process and I could always search and find an answer to any questions I had along the way.

Many thanks!
Don.