Bowser’s SPX

[Bowser]

Ahoy SeadooForum,

This build thread serves to archive the trials of my first water craft, a ’95 SPX. It was purchased in March 2022 with a known issue of fuel not getting to the carburetors. I am a first-timer at fiddling with two stroke engines but find forums a wealth of info, so here I am.








Structurally the hull is great; what I expected for a 25 year old ski that has changed owners a couple of times. Previous owner intended to restore this craft but lost interest- I did not get much history on it otherwise during the sale. The PO said he replaced the solenoid, mpem, and spark plugs.. the motor fired up manually with premix squirted into the cylinder + START pressed. To get it functional again I intend to replace fuel lines/ filters, replace pulse line nipple at the crank case, and properly rebuild the carburetors. There are signs of previous entry in the carbs, a la damaged screw heads, that may take some extra effort to correct.








I’ve been documenting the repair process & to-do list building. Intending to keep this thread updated as I go as well as post questions for repairs, replacements, etc.
Proud that I bought this SeaDoo as my first; BRP makes wicked vehicles and I’ve come to find this SPX is a perfect project for me.

 

[mikidymac]

I would not mess with the pulse nipple on the cases unless it is damaged.

 

[Bowser]

Yes that's where I'm hoping for some guidance because it is damaged- snapped clean off the motor block.



From yourself and others I've learned alot so far but have not found the best solution for this yet! Unsure if I should:
A) attempt to remove & replace the broken nipple or
B) press a new, smaller fitting over the old

Any suggestions are appreciated. The replacement part number itself has been elusive to me in the parts catalogue.. It's just hard to tell if the nipple is removable at all or if it'd be worth risking debris in the crank case.

- - -

Made progress on the carbs and will be ordering an OSD Marine rebuild kit soon. The needle valves were very gummed up, needle arms bent, generic springs, dirty filters etc.

 

[mikidymac]

Unfortunately that engine has a lot of corrosion damage so you aren’t going to just be able to press a new one in. You could try tapping new NPT threads with a lot of grease on the tap and roll the dice. The correct fix would be to go all in with new clean replacement cases.

 

[Bowser]

Thank you for the advice, so I gather removing the old fitting is not possible.

I do have a tapping tool to carve threads into the brass remnants but am curious why pressing in a new, barbed(?), fitting is not advised. I assume it's due to air leaks but seems like a simple solution using the right sealant. The pulse line crank case opening is ~4.5mm for ref.
Agreed that replacement cases would surely solve it; ability & budget are limiting factors so I'd like to weigh options

 

[mikidymac]

If you can get the broken piece out and find a new barb to press in with some JB weld it should be fine.

 

[Bowser]

Alright I’ll practice removing the brass on a spare crank case that is identically broken, thank you for the suggestions. When I bought the ski it came with two seized up motors: a 657x and a 720 power plant. In the off season I figure I can harvest and part out what I don’t need.



SO what have I done so far -

- Remove & clean air box, flame arrestor, and every screw I get my hands on en route to carburetors.
- Remove carbs, revel in their glory, & disassemble.
- Remove fuel carrying hoses, clean fuel filter reservoir, replace fuel filter, O-ring, and selector valve & knob.
- Clean the hull exterior: remove old registration, mitt wash, clay bar, scrub storage lid, & remove grab bar. Blow out acorns & dirt from impeller grate.
- Desiccate & vacuum interior of hull. Discover bilge finds: M5x25 screw, circlip for oil injection line, a M5 bit, couple of washers, and a snapped machine screw still stuck in the nut. The circlip I’m really happy finding since it’s so small and I glanced over it in the shop-vac bucket.
- Resurface the seat partially with PlastiDip and cover major rips with “657 purple” duct tape.
- Acquire trailer, cover, & build a solid stand.

 

[etemplet]

Yes that's where I'm hoping for some guidance because it is damaged- snapped clean off the motor block.

View attachment 58559

From yourself and others I've learned alot so far but have not found the best solution for this yet! Unsure if I should:
A) attempt to remove & replace the broken nipple or
B) press a new, smaller fitting over the old

Any suggestions are appreciated. The replacement part number itself has been elusive to me in the parts catalogue.. It's just hard to tell if the nipple is removable at all or if it'd be worth risking debris in the crank case.

- - -

Made progress on the carbs and will be ordering an OSD Marine rebuild kit soon. The needle valves were very gummed up, needle arms bent, generic springs, dirty filters etc.

I don't know how that fitting is held in place but if it is like everything else it is pressed in and not a very tight fit. I would get a proper sized "easy out" and a small propane torch and warm the area just a bit. the fitting may come out easily.

Next level. I think you can drill the fitting and catch the debris inside the engine. You can remove the rotary valve cover and be able to reach in and place an oiled up cloth under the fitting. Those cases are cleanable in place. I've cleaned several cases with crap in them and got them dang near spotless. Just takes some diligence.

When I put a fitting back in the engine I use Loctite 609 or equilivalent as long as the fit is in good snug. Try to get the fitting "out" that way the hole will be intact.

From experience and if that was my personal ski, I'd pull the engine, remove the mag cover and have a look inside (sometimes there is much corrosion in the housing sure to give you trouble later on).I'd also check the rotary valve clearance and rebuild the starter and of course clean and paint. In general you have to consider that everything is bad on these skis that way you will not be surprised.

Did you do a compression test?

 

[Bowser]

I appreciate the thoughts etemplet; it relieves much of my worry. I will try to pull out the old brass and press a new fitting in first. The old brass is ~7mm in length.
I’ll use a standard screw extractor but may buy a straight flute extractor as I read this form is better for this situation. I’ll hit it with some heat to loosen the bugger either way.

No compression testing yet; I’m hesitant to crank the motor until it’s primed with oil/ fuel. The oil injection lines fell apart so I’ll cut new tygon and replace & prime. If there’s no worry cranking with no fluids I’ll make it a priority to get that data.

- - -

Replacement parts for the trailer are in the mail; two frame struts and a bushing kit for the leaf springs straight from EZLoader. I will rust reform the leaf springs, spray paint black, and order a winch to water test the beast soon.

OSD Marine was a big help in buying replacement pieces for the carburetors. Proper spring weight & needle sizing came from SeaDooSource and is attached below for anyone else looking for ’95 SPX specific info. Realizing now I forgot to order a needle arm/pin set; the current set is bent so I guess it is best practice to replace these too.

 

[Bowser]

- Brainstorming request before repairing the pulse line fitting -

Hoping for suggestions on which of the three options would be best to install:
A) Stainless steel 5/32" tube into 1/16" NPT
B) Aluminum alloy 4 mm tube into 6mm bulb
C) Brass 4 mm barbs into 6mm barbs



I have a Dremel tool with metal cutting discs to shorten the insert to prevent contacting anything in the crank case. Concerned that option (A), SS fitting, won't cut well plus having to find another piece to screw onto the threads may be a chore. I'd need to cut off the SS bulb tip since it's too large to push into the case.

I'm leaning towards choice (B), Aluminum alloy, so long as I can cleanly shorten/ remove the bulb tip on the 4mm side.
Intending to use JB Weld Cold Weld Formula (24 hr. cure type) or Loctite 609, per etemplet, to seal the chosen fitting over the snapped off brass.

- - -

The trailer frame is now fixed. EZLoader was a very EZ company to work with for this frame replacement. Mounting hardware for the winch and bow stop are soon to be ordered.

 

[Bowser]

Before I proceed to turn over the motor I need to run this finding by the forums-
In the intake manifold I cleaned out coffee-brown colored grime and am hoping this is not a symptom of greater concern.
The grime was uniformly coating the surface of the manifold plumbing; no pools, no shimmer of metal flakes, just a thin layer of brown. It wiped off easily as it was fairly low viscosity. The throttle butterflies on the carbs also had the grime as these are closest to the intake manifold/ carb junction.
I’m really hoping this is just residue from improper storage, maybe dirty fogging oil, but want to make sure it’s not something major. Any suggestions appreciated.

- - -

Progress updates:
I epoxied the holes in the hull where the non-slip mats previously were to prepare for test float. Hardware to mount the winch & bow stop are in the mail. Trailer registration to be done next time I’m in town.

Carburetor is cleaned thoroughly. Replacement pieces at the ready to install.

Oil drained and oil filter replaced. I am reusing the oil and will be adding XPS oil. Intending to premix some oil into the fuel for the first startups and trials..

Fuel line and oil injector lines to be installed soon while I muster the courage to fix the pulse line nipple.

 

[Bowser]

Alrighty so -

Rebuilt the carbs however the springs do not fit and lift the needle valve arm out of their slot, not flush as it should be. Using what I thought was the correct 80 gram needle valve spring I guess the next step is to order the 65 gram springs since they are shorter?
Maybe the PO swapped carbs on this model.. The 80 grams seem too long; I hope the fraction of a millimeter difference corrects it with the 65's. Using new needle arms/pins to rule out deformation of these pieces too.

I installed 1.2 Viton needles as recommended; will replace if the PO did end up swapping carbs.

 

[mikidymac]

No. You can’t just start swapping parts. Something is wrong or you didn’t buy genuine Mikuni parts.

 

[Bowser]

Thank you for the reply. In my haste I gave up when the 80 gram spring seemed too long. The next day I gave it another shot and screwed the pin in all the way and voila, the needle valve arms laid flush. I did have the proper spring weight after all- I guess I should have had that celebratory beer after installation and not during.
I need to finalize the needle arms and bend them down <1mm to make them perfectly flush before reinstalling the carbs.

- - -

Say a prayer to Poseidon, as of this posting the brass fitting is curing with JB Weld into the crank case. I intend to connect the pulse line using vacuum tubing so it is a bit more pliable and less stress on the repaired nipple.



Tygon oil lines installed and to be bled more.
This week I’ll turn over the engine. To wake the motor from its deep sleep I will squirt a teaspoon of premix into each cylinder, prime the fuel lines, and mist premix into the carbs while cranking. Premix fuel will be mixed at 1 gal. non-ethanol fuel /5 oz. XPS oil.

 

[JC-SUPERJET]

Be aware that IF the Vacuum Tubing is too soft and too pliable, the Vacuum Signal Strength is weakened if some of the Pulse Energy is wasted collapsing a too soft Hose.

It's a Goldi-Locks problem: the Pulse Hose has to be Stiff enough to hold its shape and not yield/flatten, but Soft enough to absorb the Vibrations and make the Bend without Kinking.

Generallly, most OEMs use Fuel Line as Pulse Lines. Some even have pre-formed Bends in them.

 

[BBird]

Ahoy SeadooForum,

This build thread serves to archive the trials of my first water craft, a ’95 SPX. It was purchased in March 2022 with a known issue of fuel not getting to the carburetors. I am a first-timer at fiddling with two stroke engines but find forums a wealth of info, so here I am.

View attachment 58515

View attachment 58516

View attachment 58517


Structurally the hull is great; what I expected for a 25 year old ski that has changed owners a couple of times. Previous owner intended to restore this craft but lost interest- I did not get much history on it otherwise during the sale. The PO said he replaced the solenoid, mpem, and spark plugs.. the motor fired up manually with premix squirted into the cylinder + START pressed. To get it functional again I intend to replace fuel lines/ filters, replace pulse line nipple at the crank case, and properly rebuild the carburetors. There are signs of previous entry in the carbs, a la damaged screw heads, that may take some extra effort to correct.

View attachment 58518

View attachment 58519

View attachment 58520


I’ve been documenting the repair process & to-do list building. Intending to keep this thread updated as I go as well as post questions for repairs, replacements, etc.
Proud that I bought this SeaDoo as my first; BRP makes wicked vehicles and I’ve come to find this SPX is a perfect project for me.

Working on a 99 SPX, love it. Attached a current before/after. Will follow your build, if I can help I will!

 

[Bowser]

- Thank you for the pertinent reminder JC, I can understand the trade off of pliable vs. loss of pressure with the pulse line. I will buy a foot of vacuum tubing just to test the theory and report findings. Still have plenty of fuel hose to swap in if needed. My pulse line is already slightly compromised due to the crank case nipple repair being a smaller opening than the OEM fitting.

- BBird best of luck with the resto; looks great already. Nice & sharp livery really freshened it up! I am in VA too on the Potomac river.

- - -

Crank case fitting for the pulse line appears to have set well. Successfully bent the needle valve arms down flush on the carbs too. This afternoon I plan to install the fuel hoses, new selector valve, and fuel filter reservoir. Tomorrow I'm buying a quart of XPS oil, proper fitting gaskets, and registering the EZLoader trailer.

 

[Bowser]

Well the motor spins smoothly but no luck with combustion. Video for reference -

I'm mildly stumped on what to do next and could use some suggestions please.
With the key plugged in the 'Doo beeps twice. Fuel lines are primed as far as I can tell; will check the fuel filter reservoir to confirm it's full. Fuel selector valve set to ON. New spark plugs installed for the test. I may have an auto shop gauge the health of the battery but the trickle charger had it fully charged.

One fix-it video I saw cranked the SPX motor for 20-30 seconds before coming to life; maybe I just need to generate enough suction from the pulse line to feed the carbs? Just trying to avoid damage to the motor & starter and hesitant to crank the motor for too long. Squirting a half teaspoon of premix into the cylinders & carbs with each test.. a little throttle here and there with the choke pulled out 75% of the way..still no dice. I intend to make a compression gauge in the meanwhile and will report findings.

 

[BBird]

I have had to crank them multiple times before it “hits” when they haven’t been started in a while. I usually set in an oversized battery to make sure there is plenty of juice for the cranking. I do cycles of about 3-5 seconds of cranking and 15 seconds of rest in between to make sure I don’t overwork the starter. One other simple check is to use an inline spark tester. It is basically a light that goes inline between the spark plug and the wire, and visually confirms spark. This has been super helpful when I thought it was a fuel problem, and it ended up being a spark issue, even on skis that just ran fine in the water recently.

 

[Bowser]

- BBird thank you for the assurance that it’s normal to crank it til the cylinders catch fuel. I turned it over in a similar fashion yesterday evening; 3 - 5 seconds on the starter and let it rest awhile before trying again. While unsuccessful, the motor did quicken a few times, blow exhaust out the back, and presented new symptoms.

Next hurdle is diagnosing why fuel wisps out of the top of the carb and the motor still won’t catch. I can feel air puffing out the top of both carbs with my hand. On a few tests, a squirt of fuel would come out or most often a wisp of light grey smoke. Video for reference -

The Mag carb can be seen puffing out fuel by the quick darkening on the 12 o’clock position of its throat. From what I’ve read this could be due to rotary valve mistiming?

IF so I’ll get to opening the RV and inspect the carbs in the process. Will admit that the carbs’ needle valve arms could be bent ever so slightly more flush but I don’t think this minutia would cause air to rush out the top..

While the RV is off I guess it’s good practice to replace both RV seals too- the formed & circular O-rings.

I’ve removed the battery for charging and will take it to an auto shop to gauge its health. The pulse line nipple I repaired does not seem to be the issue nor the vacuum tubing I swapped in; so far it’s firm and doesn’t collapse any. An in-line ignition tester and compression gauge are in the mail for more data collection.

 

[BBird]

If I read it correctly, when you bought it you said it ran on premix squirted in the carbs. If it ran then, RV is probably not the issue and takes a degree wheel and patience to set. Try putting the airbox on and getting it to run. They need the vacuum pressure to run right. Wouldn’t be afraid to crank on it for a while after you verify spark. Its taken me 7-8 crank/wait cycles to get things to hit after rebuilding the fuel system.

 

[Bowser]

Results are in.. compression testing yielded poor prognosis:
50 psi MAG cylinder
100 psi PTO cylinder



Battery testing showed strong charge so that variable can be eliminated:
371 cranking amps & 13.6 volts.

In-line spark plug testing showed:
Spark strong on MAG
Spark slightly weaker on PTO

In trying to get the motor to stay running I installed the flame arrestor & airbox; everything tested in a similar manner as before. Motor still wouldn’t take, some exhaust came out the rear but it wouldn’t keep running. I trust the compression gauge too; tested it on two separate occasions, WOT, and results were equivalent.

Any recommendations for online rebuild shops would be highly appreciated. I intend to call around but could use pointers on what may be needed and who’s preferred.
Choices include: SBT, Group K, Westside Powersports, SES, and FullBore. The prior being pricier and the latter being hit-or-miss customer reviews.

I was not intending to open up the 657x but I’m too eager to succeed here to bail & sell the beast. I can learn and am patient to make sure this is done right. I WILL ride this SPX with a wetsuit on in winter if it comes to that.

- - -

In other news I will begin parting out the 720 Rotax motor I have lying about to help cover this deepening restoration money pit.

 

[JC-SUPERJET]

For future reference, Compression Tests CAN be done with the Engine out of the Ski.

All that's needed are a working Starter, Battery Cables and a Battery.

Can even run them outside of the Ski, but that's more work....

 

[mikidymac]

Engine is toast.

Stay away from SES and FullBore, you have been warned.

Group K is the best there is but most expensive.

SBT will get you on the water faster than anyone but quality is average and nothing more.

 

[Bowser]

Thank you for the confirmation ^^ . And noted JC, any future motorsports purchases will be accompanied by a compression gauge & battery.

Weighing options on how to get this ski working reliably, I think it’d be best to replace the whole motor. It’d be worth the peace of mind to have it entirely rebuilt; clean cavities, resurfaced, fresh gaskets, bearings, etc. In harvesting pieces off the extra 657 & 720 Rotax’s I have there is some awful corrosion and rust I’d want renewed.

I hope to cash in the two extra core motors with my core; intending to work with SBT for this step. There is a PWC repair shop an hour from me that I may commission to remove & install the motor properly.

- - -

I can’t tell if this flywheel puller is the right size or I am being air headed. The threads on the puller (P/N: 295000106) don’t bite into anything on the inner surface of the plate nor does it look like there is anything for the threads to bite into anyways? I contacted the manufacturer but they couldn't offer any advice~ I'd rather use this tool instead of a universal puller.