'97 GTX Build (Cutting corners, gambling on parts, etc.) Pitchforks and popcorn welcome.

[travial]

Hey guys, first things first, I'm loving all the info on this forum. You guys know a lot of stuff, and I've learned a ton in the last couple weeks. Here's the deal: I was browsing Craigslist last month, and I saw this cool looking boat jet ski combo thingy. The guy was selling it for $1500, and it was about an hour-twenty away from me. I felt a strange enthusiasm for this thing, and a couple days later I was driving it home. Trailer, '97 GTX jet ski, and shuttle craft, for $560 plus an old snub-nosed S&W revolver.

Just a little background real quick, I knew Jack schitt about jet skis when I bought this (to put it in perspective, I didn't know what a rave valve was two weeks ago, I thought it was some sort of air filter ma-jiggy), but I figured how hard could it be to fix one of these things. I mean, the guy said all it needed was a piston, and it looked in decent enough shape. Well, I kind of botched the whole inspection process, as you can imagine, and it turns out it needs way more than a piston. But, seeing as how I didn't really pay too much for it, I can't in good conscience throw a $900 SBT engine in it, so instead I'm going to try to get it running as cheap as possible. Chinese parts, used parts, reused parts, all the things you guys are going to cringe at and scold me for. If anything, it'll be a fun case study, and in the end maybe you can say "I told you so." Ok, here we go:



There she is. What a beaut! Driving it home 60 miles from Morganton, GA. The trailer tires are dry-rotted AF, but, I've had good luck driving with dry rotted tires before, and this time was no exception.



Pulled the head and it doesn't look pretty. Cylinder is scored too. The dude specifically told me the "cylinder looks good, it just needs a new piston." Bottom line, I was woefully unprepared to comb this thing over, and the 3 minute youtube video I watched on "how to buy a used jet ski" right before I rushed out the door helped surprisingly little. Even still, I think I got an alright deal on it, and still would've bought it knowing everything I do now, just a little cheaper.

Well that's all for tonight, here's some spoilers for next post though: I bought a cheap-ass used, disassembled engine out of a guys shed ($150), and my Chinese top end gaskets ($10.95) and Chinese carb rebuild kit ($13.95 for both carbs) just came in today, so buckle up, this is happening!

 

[mikidymac]

The only thing I have an issue with so far is the Chinese carb kits. Good luck with those but I think you would be ok with the cheap Gaskets.

 

[DanSquires]

For the most part, go for it. But, do not use anything other than genuine Mikuni carb rebuild kits. The 13 dollar kits simply do not, and will not, work. The diaphragms are the POS and usually are the cause of those kits to be garbage.
Nice pickup on the shuttlecraft though!

 

[Chester]

An SBT engine is really cheap, why not use one?

Chester

 

[mikidymac]

I think it’s the thrill of the what if.
But the carb kits are a never if.

 

[AKnarrowback]

I hope it all comes together for you.

 

[travial]

Thanks for coming along for the ride y’all. Chester, a 787 engine from SBT is like 900 bucks, which is a bit out of the “cheap” range on my economic scale. I can buy a running jet ski for a few hundred more around here this time of year, and save the hassle of yanking and installing an engine. In fact I seriously considered just scrapping this one, parting it out and buying another GTX or GTI (There’s a guy ten minutes from me selling a nice looking ‘03 GTI 951 DI for 1000 bucks, 110hrs on it), but I’m a sucker for bringing dead stuff back to life I guess.

Miki, I’ve read your excellent carb rebuild post, and I’ve seen elsewhere a lot of cautionary tales about the cheap rebuild kits, But I haven’t seen anyone talk about their first-hand experience with them. How do we know these kits are so bad? Who is trying them? I feel compelled to take one for the team and be the guinea pig here...

 

[Ankeneyou]

I've tried them. My first ski was a 97 GTI with the 717 back in 2011. I went all out with SBT platinum reman, rebuilt everything, etc etc. I used the SBT carb kits and after many many hours of learning and wrenching I went for the water test. It ran ok, but could never get rid of a low end bog and then it would load up horribly in a no wake zone and take forever to clear out.

I tried everything to fix it, tuning low speed/high speed, cleaning carbs again, new check valves on tank, but nothing worked. I finally took the advice here and got mikuni kits and the ski was 100% immediately on the stock needle settings. I was so frustrated I almost sold the ski before that.

8 years later and 30+ skis I've learned that the only thing you buy from SBT is traction mats.

If you get a Chinese kit, compare it side by side to the mikuni you will eventually be buying and then you'll understand [emoji6]. Good luck!

 

[mikidymac]

I have seen it first hand too as have many others on this site.

They technically work but you will experience flooding, bogging and possibly engine damage. They have been proven bad over and over. It’s not an assumption or something heard second hand, it’s a proven fact.

Just trying to save you at least one headache but if you don’t believe me then try them. Here’s your preemptive I told you so.

 

[Chester]

We've all tried them. The fuel pump gaskets leak when you do your pop-off test. We are actually trying to save you money and grief. By the time you pull out that rusty crankshaft to replace the seals and possibly replace the crankshaft, replace the pistons, and bore out the cylinders, you will be further ahead with an SBT engine with a 1 year no fault warranty. Learn from the mistakes of others, you can't afford to make them all yourself.

Chester

 

[AKnarrowback]

The old saying "you get what you pay for" is very true when it comes to carb kits.

 

[travial]

Well, I opened the carbs up last night and they were pretty much spotless. I ended up using hardly any of my chinese carb gaskets, as the ones in there seemed in good condition, and of superior quality.

As you can imagine, I fore-went the JIS screwdriver in favor of the "free" Harbor freight screwdriver. The tip looks very JIS-y, and feels like it makes solid contact with the screw head. My theory is HF knows people will use these for JIS and phillips applications, and have developed a hybrid-tip bit. The larger philips bit worked great on all the screws except the tiny clear plastic flap. One tip though, downward pressure and shaft alignment is key, especially if you're possibly using the wrong screwdriver. Leaning down on the handle with your chin (yeah, the thing on your face) provides plenty of downward force and allows you to keep the alignment perfect while twisting.
These are before cleaning.Jets were all clear.
Here you can see the quality suffering with a Chinese gaskets. The Chinese one was a diamond shape, not a good design. Keep in mind this was from the $11 eBay gasket kit ($.5.50 per carb), I can't speak for WSM or SBT. On the left is the one that I reused, it looked and felt fine and was better quality.

Here's the old and new diaphragm, this is the only part of waffling on, which one would you use "if you had to"? Heads up, one of these IS going back in the carb, so choose the lesser of two evils. I think the old one is genuine Mikuni? It looks in decent shape aside from a little warped-looking places, not sure if that was there originally though. I'm inclined to reuse the old ones, based on how bad people rag on the non-OEM ones. Going to attempt the pop off test in a bit here (reused the old springs)...

 

[mikidymac]

If there is any question in your mine on the diaphragm I would say use the new one. It is obviously molded wrong and too thick and rigid so I can't wait to see it give you fits. That and I have a spare "I told You So" I have been waiting to use.

 

[DanSquires]

That and I have a spare "I told You So" I have been waiting to use.

LOL

OP:
Red button is Genuine Mikuni, and the diaphragm is almost always the crappiest part in a knock off carb kit. Do not use it.

 

[GGuillot]

If anything, it'll be a fun case study, and in the end maybe you can say "I told you so." Ok, here we go:

You said that right, it'll be a fun case study going cheap as possible. What could possibly go wrong? But good luck and keep us posted...

 

[Spimothy Leary]

Nothing wrong with building this up with swept off the garage floor parts, you won't be the first or the last to do that, and there are lots of success stories and failures. A friend of mine just did that recently with a 787 using assorted parts from me and another buddy that had stuff laying around, its still running 3 months later but no guarantees over the long term.

One side note on the Screwdriver.
First, that free HF multi screwdriver is one of my favorite around the house (not the garage) items, good grip and surprisingly durable tips, For 99% of applications, it works perfectly, so I use it for simple stuff inside the house with no issues.

However for those 1% (stubborn screws), there is just no substitute for JIS, particularly when working with Mikuni/Honda/Kawi/Toyota. It was generally a non issue with other manufacturers. I learned that lesson the hard way when stripping down a dozen or so old carbs I had laying around to steal all the guts out, and especially when I was messing around with Kawi 150's.

With the carbs and the Kawi's after stripping a couple of screws and subsequently using many bad words and exaggerated hand gestures I bit the bullet and bought a Vessel 980 series JIS set (ebay) and I have to admit they are flipping awesome screwdrivers, even mechanic friends and my electrical guy have stopped to say "dam, this is a really f'kn nice screwdriver"

In my tool chest I probably have 50 different screwdrivers but the JIS are the first ones I use every time if I don't want to deal with a stripped screw in a hard to reach area.

 

[Ankeneyou]

Same thoughts on the JIS Spim. I have the vessel 900 series and love them. Only difference is 900 doesnt have the metal plate at the end to hit with a hammer like the 980s, but I've never had a need for it yet.

My favorite seadoo tools are:
JIS screwdrivers
Nut drivers (especially 5.5 for those hood screws)
3 different length hex sockets
Panduit zip tie gun
Milwaukee 3/8 12v ratchet (saves sooo much time)
Seadoo handheld programmer

Looking at one of those carbon seal tools now, but not sure it's worth the $120 or so.

 

[etemplet]

OK, you guys talked me into the JIS screwdrivers. I never had a set and I've been workin on stuff a long long time. LOL Perhaps they'll make my life a bit easier.

 

[Spimothy Leary]

OK, you guys talked me into the JIS screwdrivers. I never had a set and I've been workin on stuff a long long time. LOL Perhaps they'll make my life a bit easier.

I felt the same way but my "work" on doo's is/was 90% taking old salt crusted ski's apart, and the carbs were a big problem. I recommend the 980's because like mentioned above you can pop them with a hammer which comes in handy for a screw that has been painted or has some crud on the head.

The 5.5 nut driver is awesome as well for the hood screws, ebay search for Wilna 34121 Nut driver < game changer also the little tool to take apart the harnesses.

I also ordered nut drivers for the small and large hex screws on stainless clamps, makes that job so much easier than using a flat head, its hard enough having to twist your elbow 3 directions only to have the flathead slip out.

Even if you have an air ratchet (which is awesome), The Milwaukee M12 cordless ratchet is also dam handy, a bit pricey but worth it if you tinker alot on anything where tight spaces are involved or if you can't run the air hose out to the back yard, etc. Invest in some nice bits and you are good to go. I asked for one for xmas 2 years ago and now I use it all the time for everything,especially when I was putting up hurricane shutters on houses before a storm because I could put them in slow and steady vs using my cordless impact which doesn't have that super slow speed, just fast and faster.

FWIW I still love my HF deep well color coded sockets, they take a beating. I have a lot of craftsman stuff but the rest is all HF and i've been pleased. The next best (cheap) investment was buying several socket rails both short and long, helps keep sockets from disappearing into the tool box abyss.

 

[etemplet]

I'll give the cordless ratchet a look. Thanks for the heads up on the tools. I am a minimalist when it comes to tools. I'd show up at the race track (motorcycle road racing) with my single old school tool box and fix anything I needed to fix. Jet skis are a bit different especially when you are taking a lot of them apart and like you say the crusted salt water stuff can be a pain. Making life easier is cool if you have a few duckies to spare. : D thanks again.

 

[Sportster-2001-951C-Stock]

I think you'll be alright with the Chinese kit if you don't use any of the parts, especially the HS circuit reed valve you had trouble removing. Those are never bad unless the carb was woked on and the wrong one too thick or too stiff was used. If the OEM mylar reed valve lies flat over the hole (isn't bent) it'll work fine. The aftermarket reeds are too stiff I think, and cause high speed fuel delay (lean hesitation spot at high speed circuit transition).

The aftermarket diaphragms are about as iffy as any of the parts, check it VERY carefully for differences but it's not a part you use unless you absolutely have to like the original is stiff or has holes in it (hold it up to a light, or the Sun) The diaphragm should be nearly soft as a rose petal.

 

[travial]

Advice noted y'all. Update on the carbs; I ended up using the old mikuni diaphrams, here's why:

The chinese ones may have worked fine, but I wasn't impressed with the extra thickness of it. Where the bellow part is seems pretty thick comparatively, and it almost seems like the needle lever thing may hit it upon the diaphragm depressing the needle valve. Part of me wanted to try them to see what happened, but the voice of reason said to just use the old ones. They seem in fine shape, no holes, still very pliable and rose-petally, and being OEM, it was the less risky decision.


Here's the Chinese diaphragm sitting in the carb. You can see the ridge dips pretty far down and it's thicker and firmer than the OEM. I was worried about it hitting the lever above the needle.

I made up a new method for diaphragm testing though. You take the diaphragm in question and make a big "O" with your lips, and basically attempt to seal off your mouth with the diaphragm, all the while sucking in on it. if you do it right, you'll: 1) Look ridiculous, and 2) create a seal between your mouth and the diaphragm which will test for any holes/leaks in the area within your mouth (at least big leaks, you're probably not making much vacuum).

Anyway, on to the pop off test with the carbs. First, I had to change the old O-rings on the seat that I initially left in just to see what would happen when I started testing. They frothed WD-40 like crazy at the faintest pressure, so I got out my trusty O-ring assortment from Harbor Freight (The chinese carb kit inexplicably didn't come with any compatible ones) and swapped in some new ones, problem solved. The needles seemed to both "pop" around 30-32psi, and "pop" is in quotes because it's more like they hissed open rather than popping. They stop hissing and re-seat when I drop the pressure to about 20-25 PSI. What are your thoughts on them hissing open rather than popping? If I raised the pressure faster, they would pop, but going slowly at about 1 psi-per-second increase, they would hiss. I'm feeding the carbs with pressure from a 20 gallon compressor.

It's noteworthy to note that I'm reusing the needles and seats. They looked in good condition, but I feel the general sentiment on the forums is to swap in brand-new ones whenever you happen to crack your carbs open, which I can see being ok preventative maintenance advice, but, on the other hand, why change the needles and seats if you're doing the pop off test anyway, which would presumably indicate if they're bad or not, correct? Is there a known issue where the needle/seats fail often enough that the preemptive replacement is warranted?

Here's some more overall progress updates:


Peaking in the exhaust port, scoring on the bad piston. Other piston looks ok. These are standard bore.


Looking into the intake, notice the scoring on the connecting rod. This is when I realized I'm probably not using the bottom end. That, and turning the crankshaft by hand felt like the bearings were pretty bad off.



Inside the hull is utterly disgusting. I honestly don't understand how some of the debris got in here. An abnormal amount of pine needles was caked with oil and grime on the bottom. There's an oil leak I'll need to address at some point, there was a puddle of it in there.


There's mud and sand caked all the way to the top of the hull. The inside of the electrical box there was surprisingly clean though.


Puzzling scuffs on the side mirror. Do people off-road these things? My dual sport has less scuffs.



I unbolted everything to pull the engine out. It said in the manual to split the tuned pipe, was that necessary? What a PITA. Someone had installed the clamp ring rotated 180 degrees to where the screw was on the bottom rather than the top making it nearly impossible to get to.


I wrestled the engine out, and the crankshaft is definitely shot. play in the connecting rod bearings, rust everywhere, and there's still a decent amount of water in the crankcase. The crank bearings make a distinct whirring noise when spun, and they feel rough, sticky, and just awful. Quick question: Once I pulled the drvieshaft, I spun the engine and could immediately feel how bad the bearing were. Hypothetically, could you test the crank bearings by spinning the flywheel with the driveshaft in there too, or is there too many things hooked up to get any feel for the condition? Thinking for next time.

At this point though, I was at a crossroad. I thought about just parting-out this jet ski, and buying a working jet ski. I start looking at other GTX/GTI jetskis on craigslist and Facebook (to fit the shuttlecraft correctly), but at the same time I was also looking for a cheap replacement engine for it. Long story short, a guy on Craigslist had a 787 engine for $200, so I drove the 15 minutes to the seedy part of town to check it out. I pulled up to his house and its basically a jet ski junkyard with the occasional complete jet ski lying around. A fence enclosed his entire yard, containing a maze of sheds, jet skis, and parts and tools lying everywhere.



He took me into a gravel-floored shed and presented 787 bottom end amid the wreckage of literally dozens of other bottom end cases strewn onto a shelf. He pointed at them triumphantly, and bragged "see all them there? Them's were all bad, and I kept the cases." I thought, 'huh, you mean, that same pile, where you just pulled this bottom end from?' Nevertheless, he dug around some more and found the jugs, piston, and head, and procured more miscellaneous parts and bolts from a re-purposed kitty litter bucket. Surprisingly, somehow, everything looked ok, and the bottom end felt smooth and looked clean enough. He said he saved this bottom end special, because it looked so good. Said the ski had electrical problems, but the engine was good. Call me crazy, but I had a good feeling about it, so I offered $150 and drove away with it.

 

[mikidymac]

So here is your first one for free, "I told you so" on the carb diaphragms. They will hold the needle open and will not react to vacuum changes correctly.

Secondly, the needle and seat's will not work correctly if they "hiss" open. They need to pop strong and quick then close tightly when they drop about 10 psi from the pop.

 

[GGuillot]

I unbolted everything to pull the engine out. It said in the manual to split the tuned pipe, was that necessary? What a PITA

I went through a similar issue stripping mine, I couldn't get it split apart in the ski. So as I lifted the engine out with the puller first then put it in the table vice and hit it with the mallet.

There's mud and sand caked all the way to the top of the hull. The inside of the electrical box there was surprisingly clean though

Judging from a couple of the pics it appears it took on water to the left of the ski.

If there's any words of encouragement it'll clean up well, mine was pretty bad, sat in a barn and had rats living in it. Took me awhile to restore it, nearly a year, but I went deep on it to bare hull doing gelcoat work and a little bit at a time stretched over a full year to get it back to like new condition.

Your carbs are in far better condition than I'd think, but I'd still rebuild with either new oem kits or at least get a diaphragm kit and needles/seats if you want to keep cost low.

You have your work cut out, in addition to the engine/carbs, I'd remove and flush the gas tank, go through the jet pump, new oil, check bearing, impeller, wear ring, etc. And wouldn't hurt to replace oil, fuel, and water lines. Double check all fittings for good flow, don't exclude the one in the very rear exhaust, I found that one plus the one of the large lines through the hull plate completely clogged. Vent lines off the fuel tank to the hull can clog, easy to flush them out with brake cleaner. You may find the fuel sender is bad, both of my trashed purchased skis they were, you can ohm test it to find out. There is a fix that usually works on them if you get nothing on the DMM.

I concur with others on your threads, if there's any areas you want to cut corners on, the carbs I wouldn't. Ditto on the oil lines and the fuel system, minimal costs that can save lots in the long run.

 

[Sportster-2001-951C-Stock]

The metering needle has a viton rubber tip that's impregnated with graphite lubricant, over the years the rubber tip takes on a groove and the graphite is washed or worn away, they begin to stick in the seat unpredictably. The replacement needle comes with a brass seat, I've seen s replacement seat with a tiny burr inside it that damaged the needle tip. Some tuners looking for that little extra on the throttle action will polish the seat with abrasive on a q-tip to make it operate smoother, not sure how well that works or makes a difference?

Those aftermarket diaphragms look horrible to me.