99 GSX limited build/resto

[nikdseadoo]

Figured I might post up a thread to track some progress on essentially my first ski.

Back story: Ended up getting a nice dock/slip at marina 5 minutes away, had lift for the toon and two jet ski lifts. Welp, now I got two jet ski lifts to fill right! No need to ask wifey permission. Begin search for used ski, holy hell they aint cheap. Found pair of old skis and trailer on FB for $1300, sold coming to get them. 94 yamaha, 99 gsx limted trailer, Seadoo has title (sweet). Dont really want yamaha or trailer sold back for $700. Boom, 99 GSX with title for $600 can't beat that. Especially considering the guy claims it only needs a starter, woot woot!.

Guy I sold trailer and yamaha to sends me a video literally two hours after sale of it running! (win some/lose some).

First ski, don't know a thing about them, gonna learn real quick! Ton of red flags now known, but oh well. For $600 i really can't go wrong. Finally get to wrenching on her and change the starter and nothing. Seems I have the wrong key? Just gives one long Beep and nothing. So give starter straight jump juice and nothing, crap. Now I finally have the sense to see if I can spin the motor by hand.....drum roll....Of course not. So full blown thrash mode now, pull motor, top end looks suspiciously brand new, crank is straight up frozen. Oh well, two stroke is no big deal, especially these deals with no transmissions attached.

Send off crank and counter for rebuild (not SBT since 6-8 weeks out and they weld the crank making it never to be rebuilt again). Begin research and plan mods. Pro-k filters, jetting, new key programming, etc etc. Found out in the process that no oil tank, no pump nada, already on premix. Whateves. Keep finding all sorts of goodies, like bilge pump don't work, took hard hit on front port side and fiberglass is gone allowing water in.

Fast fire round:

Needs seat cover
Tons of TLC needed
handle bar pad
etc etc getting tired of typing now. Ski was in shambles.

Will post up more pics and progress updates as I have them. Still hopeful she will be on water before the 4th.

 

[mikidymac]

Keep the stock airbox and jetting, no performance to gain, just more headaches. Full carb rebuild with only Genuine Mikuni parts and full fuel system rebuild.

 

[nikdseadoo]

Keep the stock airbox and jetting, no performance to gain, just more headaches. Full carb rebuild with only Genuine Mikuni parts and full fuel system rebuild.

Curious answer. Seems rather opinionated, I understand the little if any performance gains to it. I'm more interested in the clean engine bay and easier tuning access. But the air box, rave hoses, oil system and I'm sure I'm forgetting more....are all bye bye.

Full fuel rebuild is a definite.

 

[mikidymac]

The 951 can't tolerate any water ingestion so the stock airbox is really good at keeping water out. The carbs are very lean and can suffer from a 3/4 throttle lean spot even with larger jetting simply because with a free flowing air cleaner the carbs lose vacuum signal and can't pull fuel no matter what you do. But it is up to you.
With a stock ski, there is no "tuning" they run perfect with stock settings.
You can't run that engine without the RAVE hoses being connected.
Opinionated? Yes, 30 years working on these and 30 years of seeing people blow them up. Honestly, I just want you to have a Seadoo that runs and you can have fun on.

 

[Whus02]

From what I understand, 951s tend to run better with the stock airbox, especially in cases when the rest of the motor is stock. Definitely rebuild the carbs and get the motor running correctly stock, before any mods.

 

[nikdseadoo]

The 951 can't tolerate any water ingestion so the stock airbox is really good at keeping water out. The carbs are very lean and can suffer from a 3/4 throttle lean spot even with larger jetting simply because with a free flowing air cleaner the carbs lose vacuum signal and can't pull fuel no matter what you do. But it is up to you.
With a stock ski, there is no "tuning" they run perfect with stock settings.
You can't run that engine without the RAVE hoses being connected.
Opinionated? Yes, 30 years working on these and 30 years of seeing people blow them up. Honestly, I just want you to have a Seadoo that runs and you can have fun on.

Plenty of people blow them up stock, for a multitude of reasons. I have no problem burning it down to my own mistakes, my form of control. But for a failure to happen for no reason other than its better to keep it stock.......

I run all my 2 strokes plenty conservatively. I have no fear of what I'm doing hurting the ski. And with it being a brand new motor in an old previously unknown ski with potential issues....id rather it my way.

The accelerator pump is gone too, along with the choke. Primer kit is installed.

And the rave valves will work fine off exhaust pressure. Like 99% of all other 2 strokes in the world with them.

 

[mikidymac]

Plenty of people blow them up stock, for a multitude of reasons. I have no problem burning it down to my own mistakes, my form of control. But for a failure to happen for no reason other than its better to keep it stock.......

I run all my 2 strokes plenty conservatively. I have no fear of what I'm doing hurting the ski. And with it being a brand new motor in an old previously unknown ski with potential issues....id rather it my way.

The accelerator pump is gone too, along with the choke. Primer kit is installed.

And the rave valves will work fine off exhaust pressure. Like 99% of all other 2 strokes in the world with them.

I gave you reasons but it sounds like you have it all figured out and don't need my help so I wish you nothing but the best.

 

[SabrToothSqrl]

I'd second leave it stock, but I've only owned 6 951 skis and fixed more than I can count. including a 99 GSX Ltd. I'll get the popcorn ready.

 

[nikdseadoo]

I'd second leave it stock, but I've only owned 6 951 skis and fixed more than I can count. including a 99 GSX Ltd. I'll get the popcorn ready.

Yup, you do that. Y'all are the reason forums are dying too. People only come here to search and not contribute because why? Because y'all are like a know it all wife that doesn't like change.

I got it honey, leave it stock. It's safest. Move along, your opinion is noted.

 

[Whus02]

Alright, be sure to keep us updated.
Do you have some better pictures of the fiberglass damage?
You might be able to save your handlebar pad as well, that style tends to clean up pretty well.

 

[Whus02]

Yup, you do that. Y'all are the reason forums are dying too. People only come here to search and not contribute because why? Because y'all are like a know it all wife that doesn't like change.

I got it honey, leave it stock. It's safest. Move along, your opinion is noted.

I also think that there isn't much wrong with modifying a ski. However, it is better to get the ski running well stock, before adding mods.

 

[Saludadoo]

How did you get a replacement key?

 

[GGuillot]

Opinions are opinions you can always do what you want of course. The 951 is already very high strung, it's at the very top of the food chain on the Seadoo 2 strokes. It's not the engine you want to modify, or you'll be fixing it all the time, reliability plummets.

Keep it stock, if you want to modify the 787 is a better choice to do that.

 

[etemplet]

Plenty of people blow them up stock, for a multitude of reasons. I have no problem burning it down to my own mistakes, my form of control. But for a failure to happen for no reason other than its better to keep it stock.......

I run all my 2 strokes plenty conservatively. I have no fear of what I'm doing hurting the ski. And with it being a brand new motor in an old previously unknown ski with potential issues....id rather it my way.

The accelerator pump is gone too, along with the choke. Primer kit is installed.

And the rave valves will work fine off exhaust pressure. Like 99% of all other 2 strokes in the world with them.

Sounds like you've been around 2-strokes a bit. I don't like the accelerator pump myself. One thing I'm glad to have with the 951 is choke. I've restored 2-951s... BOTH have runaway. I like having the choke right there. I guess with primers that will stop a runaway as well and if you get the carbs working properly you might solve that problem.

What you say about the raves working without the hoses agrees with what I have found. I accidently left the rave hoses disconnected and went riding the 951. I didn't notice any difference in performance.

I hope you stay around. Good luck with the ski !! Pictures and such would be cool.

 

[1of500]

Plenty of people blow them up stock, for a multitude of reasons. I have no problem burning it down to my own mistakes, my form of control. But for a failure to happen for no reason other than its better to keep it stock.......

I run all my 2 strokes plenty conservatively. I have no fear of what I'm doing hurting the ski. And with it being a brand new motor in an old previously unknown ski with potential issues....id rather it my way.

The accelerator pump is gone too, along with the choke. Primer kit is installed.

And the rave valves will work fine off exhaust pressure. Like 99% of all other 2 strokes in the world with them.

You have to modify the raves to work without the solenoid. There is a hole that needs to be drilled also need to block off the port the hose went on

 

[1of500]

Here you go

 

[Boyd12]

I had a 951 and removed the air box plumbing, rejetted and installed R-D flame arrestor. There was a noticeable performance gain and it was much easier to work on. But you must be diligent about keeping water out of it. I put more than 400 hours on it (two top end rebuilds, bottom end original). I was anal about maintenance. it was a great boat! Good luck!

 

[Gasngo]

Nice find I have been in search of something like that. Im looking for earlier carb units also.

 

[POPPS]

Keep'er stock!,,,Rav valves work to get you out of the hole, I have not heard of anyone removing them ever!

 

[nikdseadoo]

How did you get a replacement key?

I had a 951 and removed the air box plumbing, rejetted and installed R-D flame arrestor. There was a noticeable performance gain and it was much easier to work on. But you must be diligent about keeping water out of it. I put more than 400 hours on it (two top end rebuilds, bottom end original). I was anal about maintenance. it was a great boat! Good luck!

The fella on ebay that reprograms them

The ease of work is really what I'm after, if it performs better awesome perk.

Rave valves are staying on peeps! They will just run off exhaust pressure. I'm aware of the hole needing drilled. I ruined the first valve body I attempted. Whoops.

I will get some pictures and videos going. I'm sure the forum will flame me for some things,.... like the epoxy patch job thats fixin to happen tehehe Going to be a decent boat on the cheap when I'm done.

Found another GTX 951 local but he doesn't have the title whomp whomp whomp.

 

[mikidymac]

Please keep your progress on this updated.

We are not trying to discourage you from modifications and think that it is great you are giving it a go. You will be fine as long as you do your research and take the necessary precautions to keep it alive and it sounds like you defiantly will.

We typically discourage it only because the majority of people that come hear just want to have a reliable ski that doesn't have issues or take special care or knowledge. Once you modify them like the air cleaner you have to be careful who rides it to keep water out of the engine but if it is just you then you know to be careful.

 

[nikdseadoo]

Does anyone know how the bilge pump works on a 99 GSX limited?

Sorry no updates yet, been waiting on the engine parts to come back.

At any rate I'm replacing the bilge pump in this GTX and it gets power from the MPEM but what triggers it? I scoured the shop manual and cant find much. Only that it is kicked on for a while on start up but thats it???

How does it sense water if ski was to be taking it on? I'm un aware of any float?

Thanks!

 

[KyleW2]

No help from me on the bilge but wish I’d seen your thread before selling off my Pro K filters on ebay. Would have made you a deal since I’m going stock on my 951 build.

If your ski has the stock air box assembly and you don’t want it, shoot me a message with a price if you wanna sell it. I’m not in a rush since I won’t start on my RX build for a couple months.

 

[mikidymac]

No reason to get personal.

The bilge pumps are powered by the MPEM and you can actually hear them cycle once as soon as you connect the lanyard. I can't remember if they are on all the time when the ski is running or if there is an internal connection that is made when water enters the pump. I know there isn't and external float like some of the aftermarket ones.

I found this on another thread...
"Doo's tend to have a Rule 500GPH Automatic pump in them...

Cycles once every 30 seconds I think it is (when lanyards on) and if its got resistance (water on inlet) it will run until its gone.

If you'd like to make your bailers more effective remove the bailer screens get some longer 8mm hose and but a pair of rxp drains that have the bailer at the back built into the drains. This was the ski doesnt need to have much water in it before it starts sucking it out if that makes sense? <--- SurfNturf must be credited for this mod, its HIS idea not mine."

 

[nikdseadoo]

No reason to get personal.

The bilge pumps are powered by the MPEM and you can actually hear them cycle once as soon as you connect the lanyard. I can't remember if they are on all the time when the ski is running or if there is an internal connection that is made when water enters the pump. I know there isn't and external float like some of the aftermarket ones.

I found this on another thread...
"Doo's tend to have a Rule 500GPH Automatic pump in them...

Cycles once every 30 seconds I think it is (when lanyards on) and if its got resistance (water on inlet) it will run until its gone.

If you'd like to make your bailers more effective remove the bailer screens get some longer 8mm hose and but a pair of rxp drains that have the bailer at the back built into the drains. This was the ski doesnt need to have much water in it before it starts sucking it out if that makes sense? <--- SurfNturf must be credited for this mod, its HIS idea not mine."

Good deal! Thank you!!

plan on putting this to test with water hose when I get it back together. I tested the pump in it and it was fubared. I ended up replacing it with a rule 750 as it had the same amp draw/size/etc. just soldered in the factory connector.

just crossing T’s and dotting lower case J’s while I wait for engine work