1996 and 1997 SeeDoo SPXs

[95C1500]

Dropped my single battery in each one and tested compression in both skis.
96 717
Mag: 145 psi
PTO: 140 psi

97 787
Mag: 155 psi
PTO: 155 psi

I tested each cylinder twice and got the saem readings. So, looks like I'll be dumping some money into these things to get them ready for summer!

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Also, here's the hull damage on the 97.

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[spitanddirt]

Oh the fun you'll have.

Go over to PWCtoday.com and register for free. Then head to the Seadoo sub forum under technical discussion and download a FREE genuine service manual for both of the skis.

Key points for those skis that have been sitting unused:

Fuel system integrity is extremely crucial to engine longevity.

Replace all fuel lines from the original Grey Tempo lines. Those lines are not compatible with Ethanol fuel. I recommend replacing all fuel lines with Gates Barricade 1/4" fuel line because it's made to be Ethanol resistant.

Carb filters, carb filters, carb filters. I dont care if they've "been rebuilt." Do yourself a favor and pull them completely apart and check for any gunk buildup in the tiny plastic filters that are INSIDE each carb. If the carb filters are clogged, the engine will run lean and now it's just a matter of time before the top of the pistons explode.

The tiny oil injection lines get brittle and crack. When carbs are removed, replace them with Chain Saw fuel hose. In addition, you can clearly see that the hoses have oil. You you will have to prime the hoses by manually turning the oil pump. See manual.

Replacement of the voltage regulators is highly recommended. Depending on the number of actual hours on the skis, the regulators are very cheaply designed and when they fail, they cause very wierd running issues.

The 1997 SPX is the same as the 1996 XP except for color. Super fun ski. I own two 96's. The VTS unit is very prone to fail and will cause fuses to keep blowing. I recommend disconnecting power and manually locking the jet nozzle at neutral until you get the ski running well. The rear electrical box is notorious for corrosion make sure that all the ground wires are clean and corrosion free.

Both spark plugs fire at the same time or every 180 degrees of engine rotation. Do not try to remove one plug to check for spark without holding the spark plugs together. The spark plug caps can be unscrewed from the ignition leads. They can go bad too.

Be sure to check the pump oil level by removing the jet nozzles.

Finally, if you have the original Nippondenso starters do not throw them away if they fail. They are worth rebuilding. Most all "new" starters are cheap Chinese crap.

Use Ethanol free fuel if possible, and always use fuel stabilizer.

On the 1997 start with both red RAVE cap screws at 1 full turn out from seated and the water box regulator cap at three turns out from seated.


I know that's a lot, but these skis are not cheap when you ignore maintenance. And they are over 20 years old....that should say enough.










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[95C1500]

Oh the fun you'll have.

Go over to PWCtoday.com and register for free. Then head to the Seadoo sub forum under technical discussion and download a FREE genuine service manual for both of the skis.

I joined seadooforum.com and downloaded service manuals and parts catalogs already

Key points for those skis that have been sitting unused:

Fuel system integrity is extremely crucial to engine longevity.

Replace all fuel lines from the original Grey Tempo lines. Those lines are not compatible with Ethanol fuel. I recommend replacing all fuel lines with Gates Barricade 1/4" fuel line because it's made to be Ethanol resistant.

PO replaced or had them replaced 5ish years ago. I do have some 1/4" fuel hose in a summit racing cart ready to order. I'm going to check the lines when I pull the carbs. If they need replacing, they will get replaced.

Carb filters, carb filters, carb filters. I dont care if they've "been rebuilt." Do yourself a favor and pull them completely apart and check for any gunk buildup in the tiny plastic filters that are INSIDE each carb. If the carb filters are clogged, the engine will run lean and now it's just a matter of time before the top of the pistons explode.

Both carbs will be thoroughly cleaned, if not rebuilt with genuine mikuni parts.

The tiny oil injection lines get brittle and crack. When carbs are removed, replace them with Chain Saw fuel hose. In addition, you can clearly see that the hoses have oil. You you will have to prime the hoses by manually turning the oil pump. See manual.

I'll have to look again but I believe the oil lines have been replaced as well. If not, I have some chainsaw fuel hose in a cart as well.

Replacement of the voltage regulators is highly recommended. Depending on the number of actual hours on the skis, the regulators are very cheaply designed and when they fail, they cause very wierd running issues.

Now that's something I have not heard yet. I'll definitely look into those.

The 1997 SPX is the same as the 1996 XP except for color. Super fun ski. I own two 96's. The VTS unit is very prone to fail and will cause fuses to keep blowing. I recommend disconnecting power and manually locking the jet nozzle at neutral until you get the ski running well. The rear electrical box is notorious for corrosion make sure that all the ground wires are clean and corrosion free.

Definitely on my list of things to check.

Both spark plugs fire at the same time or every 180 degrees of engine rotation. Do not try to remove one plug to check for spark without holding the spark plugs together. The spark plug caps can be unscrewed from the ignition leads. They can go bad too.

Noted

Be sure to check the pump oil level by removing the jet nozzles.

At their age, I'm going to replace the pump oil in both. 75w-90 synthetic gear oil was recommended by a few on the seadoo forum

Finally, if you have the original Nippondenso starters do not throw them away if they fail. They are worth rebuilding. Most all "new" starters are cheap Chinese crap.

I will definitely keep that in mind!

Use Ethanol free fuel if possible, and always use fuel stabilizer.

Any particular stabilizer you recommend?

On the 1997 start with both red RAVE cap screws at 1 full turn out from seated and the water box regulator cap at three turns out from seated.

According to my research on the seadoo forum, they recommend the screws sit flush with the cap (at least on the rave valves; had not heard of a water box regulator yet). Why do you suggest 1 turn out?


I know that's a lot, but these skis are not cheap when you ignore maintenance. And they are over 20 years old....that should say enough.

I am very maintenance minded. I want a solid runner, not a looker.









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Thanks for the insight!

 

[spitanddirt]

FYI, I rarely have ever replaced the parts in the Mikuni carbs. Even after all these years, the rubber diaphragm have remained pliable. Unless there are actual tears or if the plastic film diaphragm for the fuel pump is crimped, the parts can be carefully removed, wiped clean and reinstalled.

Ultimately the choice to rebuild or replace is up to you.

The reason voltage regulators cause problems is because they allow AC voltage to "leak" into the DC side of the charging circuit. More accurately, the rectifier circuit in the voltage regulator fails. The MPEM and CDI unit need a consistent DC voltage level to function.

The RAVE valve's are user adjustable to achieve the crossover point RPM at which the exhaust valves open. Flush is an acceptable place to start. To raise the RPM at which they open, tighten red caps equal amounts. To lower the RPM point, loosen them.

As for the water box regulator, take it apart and check if the steel snap ring(not clamp with screw) holding the lower part of the rubber bellows has rusted away. If it has, it needs to be secured so that it doesnt leak water pressure. The water regulator is important for maximizing top speed. How much water is injected into the tuned pipe at full throttle will limit maximum RPMs. At full throttle, the regulator ports water only to the water box.

No matter what, water has to enter the exhaust stream or the rubber exhaust hose will melt even while running on the hose on the trailer!

Remove all water hoses and verify that water flows. Mud Daubers like to make nests and clog the lines.

As a word of caution, the engine RAVE valves and the water box regulator have different springs, dont mix them up.

Speaking of insect nests and clogs, the fuel tank on both skis have a venting system that gets overlooked. In the front of the hulls just under the rub rail(left side I think) there are two ports. One is for the battery vent tube which isnt used much anymore since so many batteries are AGM.

Directly behind the second one is the 7psi vapor overpressure check valve. This valve will allow the gas tank to vent excess fuel vapor pressure on really hot summer days. Remove this valve and clean using carb cleaner and compressed air.

The fuel tank can also develop a slight vacuum. This vacuum may cause fuel starvation to the engine. There is a check valve connected to the hose that runs up to the vent hole that you see when you open the storage compartment. It can also become gummed up over the years. Again, clean it out using carb cleaner and compressed air.

Be sure to verify the correct orientation when reinstalling both the overpressure valve and the inlet check valve.

The fuel tank should be allowed to draw outside air in with zero restriction as the fuel level drops, but hold pressure.

As for fuel stabilizer, any stabilizer is better than none. It's the Ethanol that's so bad for boats and other vehicles that sit for long periods of time with little use.

The 720 motor is more bulletproof than the 787. But dirty fuel systems are always a fast track to shelling out a motor.

Finally, there is an insane debate on what everyone uses for 2cycle oil. I personally use Citgo Sea N Snow semi synthetic and have for the past decade. Its anywhere between $16-$20/gal. It's the same as Mystik JT4 available at Academy Sports. I use it exclusively in my skis. (I also have two 951 powered skis.)

Just dont get suckered into buying $45/ gallon oil.



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[95C1500]

Now that I've spent some time poking around on these things, I can comprehend all of what you're saying @spitanddirt. Definitely should have cleaned the check valves when I cleaned the tanks out. Oh well, I've got time.

Forgot about these things for a while. Was on furlough due to Covid for about two months. Also was busy finishing up another semester of college and working on the truck (AC repairs). Swapped the toolbox from the trailer to the truck because my $900 cover rotted out. This sparked my interest in them again.

Since compression was good to go, I started ordering parts.
- Fuel valve and gasket for each
- Fuel filter for each
- Rave valve gaskets for the 97
- carb base gaskets for each
- oil injection line kit for each
- gallon of the expensive XPS synthetic 2 stroke oil
- induction tach to set idle

Things I still need to order
- Carb rebuild kits (more on this later)
- Registration letter/number kit for the 96
- Air cleaner seal for the 96
- Choke cable set screw on the 97
- carb bracket to exhaust bolt on the 97
- carb bolt washer on the 96
- water regulator boot for the 97
- Tires, 2x4 runners, padded marine carpet, taillights, hub bearings for trailer

Started off by cleaning the sludge built up in the hull of each. Then pulled the carbs off the 97. The only snag was a stripped out set screw on the choke cable That was a long 45 minutes. Also found the air cleaner cover seal was missing on the 96.

A few days later I pulled the rave valves off the 97 and cleaned them. Also pulled the water regulator and found the clip had rusted completely and punctured the boot. I'll secure the new boot with a ziptie.

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At this point, I decided pulling the trailer into the driveway and working in the sun was not ideal so I built a couple dollies out of some furniture dollies and 2x4s. They are safely tucked in my parent's garage temporarily. They sit just low enough to give me a back ache after working on them for even a short period of time.

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At this point, I built a pop off tester and this is where things kind of went sideways. The po never could get the 96 to run correctly. When I checked pop off on the mag carb, all was well. No leak from the needle, pop off was in spec. The PTO carb on the other hand had a huge air leak out of the pump cover on the carb. I believe I found out why it wouldn't run and would bog out.
I moved to the 97 mag carb and found the needle and seat was leaking. Pop off was also in spec. Didn't bother checking the PTO. 2 out of 4 carbs needing a rebuild is enough for me. I went to order the OSD "back to oem" kits and they are out of stock until at least June 10th thanks to Commifornia not allowing Mikuni to ship parts (I'm guessing because the state is on lockdown?). So that's a bump in the road and delaying me a bit.

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Since I had time to wait for carb rebuild kits, I decided to pull the gas and oil tanks out of both to clean them out. I siphoned all four out and then used fresh gas to cut the build up. Let them sit overnight, dumped them, then reinstalled. Seemed to do the trick. Some brake parts cleaner and a rag worked wonders for the gunky build up on the outside. Also replaced the fuel valves and filters on both.

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Moved on to the oil injection lines. The old lines weren't even clamped on. Just slipped onto the nipples. The kit for the 96 was barely enough line to work and the 97 had several inches of excess. I should've cut to fit but, meh.

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With nothing left to do at this point, I decided to "restore" the hood of the 96. I used a map torch and heated the plastic to make it look new. It won't last but it looks a little better.

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Once the carb kits are back in stock, I can really get moving on these. On my next day off, I'm going to address the trailer.

 

[Pinger]

I just tried uploading the manual (717 and 787) but file 'too large'.
If you haven't as yet sourced it and want it - PM me an e-mail address and I'll forward it to you.

 

[95C1500]

I just tried uploading the manual (717 and 787) but file 'too large'.
If you haven't as yet sourced it and want it - PM me an e-mail address and I'll forward it to you.

One of the first things I did. Thanks though!

 

[95C1500]

I've got quite an update. I'll split it into two posts. Picture heavy as usual.

I'll just get the trailer out of the way.

New tires, new runners, new carpet for said runners, new bearings, new bearing covers. Also bent the beat up fender back into shape.

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[95C1500]

This is the exciting part. Finally received my carb rebuild kits which were backordered until June 10th. Rebuilt all 4 carbs monday night after work. I think I inhaled a full can of carb cleaner (used in a ventilated garage with a fan blowing on me). Had a headache the whole next day lol.

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Set pop off on both sets and got them installed in the 96.

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Got the throttle, choke, and oil injection pump adjusted and held the pump open at at start up to force oil through the lines. Took way longer than I felt comfortable but she's getting oil now.

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She purrs. (No sound because I can't figure it out)

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I'll get the 97 done after work friday and hopefully back them into the lake on the trailer to see if they run in water. After that, I'll fix the hull of the 97 and register them. They should be lake ready at that point.

 

[mars2878]

Any updates?