Restoring a 94 GTX have an issue

[Sportster-2001-951C-Stock]

Make dang sure that low speed circuit inside the carb isn't clogged, it can be a real bear getting the junk out of there. I agree the aftermarket carb kits don't make the cut, some of the parts are inferior and if you use them you can hear that finicky Mikuni laugh at you while it acts completely stupid.

I'll say it again, make certain the low speed circuit isn't clogged, not even a little bit clogged! Then clean it again.

"It seems no matter how far or what direction I turn the screws nothing drastic happens. "

The idle mixture fuel comes from the low speed circuit, idle mixture adjustment doesn't work properly if there's junk in there. It also will be difficult to dial in if those aftermarket parts are screwing up the fuel metering diaphragm action. Check pop-off to confirm it's close to spec, not in outerspace. Correct spring and metering lever position to fine tune both within 1psi of the other. Never bend or modify the spring in any way, this ruins it.

This symptom sounds like lean hesitation, clogged low speed circuit causes lack of fuel (thus lean) assuming your carb parts are functioning correctly.

If it starts and runs on the trailer then before you can diagnose further with any confidence, the jet pump must be submerged. This can be accomplished in a testing tank, on the trailer at the boat ramp or in the neighbors swimming pool, but not on the trailer on dry land.

 

[laptop4079]

Okay update time. I went off the PO information when he said he replaced all the fuel line. He did with 3/16 line. I have no idea how he was able to get it over some of the barbs but I got it all cut off and replaced with the correct 1/4' stuff and cleaned the tank while I had it out. He also neglected to clean out the selector switch. After doing all that the ski ran great for longer than it ever has. It ran so well I started getting suspicious so I pulled it in to dock and as I was slowing down I noticed it didn't want to idle so I kept the rpm's up and killed it myself with the button. I waited a few minutes as I messed with my tachometer and went to restart it and nothing. Cranked but no start, not even with starting fluid or choking it. It would sputter and sound like it wanted to start but just wouldn't. I pulled it out of the water and put a charger on it because I ran the battery a little low trying to start it and it wouldn't even start on the trailer. So I figure it had a spark problem so I pulled the plugs and cranked it and it had nice strong blue spark on both cylinders. Then I thought the RV might have come out of time so I pulled the carbs off and checked it and it was still lined up perfectly. I am currently at a loss. The only thing I haven't done is check compression. Before it had 157/160 I need to borrow my neighbors gauge or go buy one to check it again

 

[mikidymac]

Never clean the selector, replace them. They usually get old and suck air and no cleaning can stop that. Sometimes it makes it even worse.

With spark and starting fluid and still not running you need to check compression before doing anything else.

Also never use starting fluid as it removes any lubricant.

 

[Ckrawiec]

Have you cleaned/rebuilt the carbs? If not, save time and aggravation by only using OEM Mikuni kits....all others will “most likely” bring grief....speaking from experience. Based strictly on age of ski, I’d start there.

 

[Sportster-2001-951C-Stock]

I've seen starting fluid lift a head right off a block before, pretty harsh stuff.

 

[laptop4079]

I know how harsh starting fluid is especially on 2 strokes. I used it as a last ditch effort to get any life out of it. Carbs were rebuilt with an sbt kit before I found this fourm after I ran into problems. I'm new with pwc's forgive me haha. If the compression checks out I'm going to rebuild the carbs again with mikuni kits. I've started sourcing items for the kit, the only problem I've run into is on seadoosource it lists my spring as 270500130 but it's discontinued on osd marine. Where else can I get one from?

 

[Ckrawiec]

Did you by chance keep the old Mikuni parts from the carbs? You can get OEM Mikuni kits on Amazon....like $100.00 for a duel carb setup.

I removed my SBT rebuild kits (this past weekend), re-installed all the previous Mikuni parts, made sure everything was squeeky clean and all passages flowed clean with carb cleaner and the ski came back with a vengence.....pure power, no throttle hesitation on water, running better than ever.

Avoid "starter fluid" if you can, use VERY VERY little if you can't.....gas in a small squirt bottle is best to dribble or a little squirt into the carbs (assuming all the covers are off, etc) and you can get the bottle down into the ski.....very doable if all the covers are out of the way.

 

[laptop4079]

Did you by chance keep the old Mikuni parts from the carbs? You can get OEM Mikuni kits on Amazon....like $100.00 for a duel carb setup.

I removed my SBT rebuild kits (this past weekend), re-installed all the previous Mikuni parts, made sure everything was squeeky clean and all passages flowed clean with carb cleaner and the ski came back with a vengence.....pure power, no throttle hesitation on water, running better than ever.

Avoid "starter fluid" if you can, use VERY VERY little if you can't.....gas in a small squirt bottle is best to dribble or a little squirt into the carbs (assuming all the covers are off, etc) and you can get the bottle down into the ski.....very doable if all the covers are out of the way.

I do but the previous owner absolutely massacred them. When I took them apart to clean them they were missing all sorts of parts

 

[Ckrawiec]

There is a great link to Carb rebuilds on Mikidymac...he has already commented up above so backtrack to his post and follow the link to the Carb rebuild...great info there.

 

[Sportster-2001-951C-Stock]

There is a great link to Carb rebuilds on Mikidymac...he has already commented up above so backtrack to his post and follow the link to the Carb rebuild...great info there.

Yes, I'm pretty sure it's a sticky, as well. Shouldn't be too hard to locate, I can post the link but someone will beat me to it?

Anyway, I use pre-mix in a bottle and squirt that down the carb throats to locate a dry carburetor(s). It's been many years since using starting fluid so honestly I don't recall what to expect. This was about the same time I saw the head lifted off a block.

I use my handy bottle of pre-mix on everything except diesels.

 

[mikidymac]

OSD Seadoo has a “back to stock” carb kit that includes absolutely everything you need.

 

[laptop4079]

Update time again! Went to the good old harbor freight and bought my own compression tester got home and checked the reading with shop air first because my old one was way off. Turns out the reason the ski didn't want to start is because it has 47 psi in one cylinder and 70 in the other. What the heck happened? according to the plugs the mixture was spot on nice golden brown color I was running 40:1 premix with the oil tank full of oil. I've only had it out on the water just under 3 hours since I got it? do rings go bad when they sit? Is it worth putting a new top end on this thing if so where can I gather all the parts?

 

[mikidymac]

The Harbor freight gauges have been known to give false readings. I would go with something a little better like the Actron ones from Autozone.
Much better to spend $40 on a tester than hundreds on a rebuild you don't need.

 

[JeremyD615]

I’ll second that. My harbor freight compression tester reads about 100psi for all four of my properly running engines... At the very least rent one from the auto parts store before you spend the money on a rebuild.

 

[laptop4079]

I agree that the HF tester is junk because my old one read 80 at 120psi but I tested it on shop air at 40 60 and 170psi and it read it correctly even if it was a short burst so I semi trust this one. Even if it was incorrect a 30 psi difference isn't good.

 

[JeremyD615]

You’re absolutely right! There’s really no telling what the cause is until you get the head off and can look at the pistons. Unfortunately I’d say you’re probably going to find some sadness in there...

 

[Sportster-2001-951C-Stock]

Bummer, I hope your compression gauge is wrong. Some of the Harbor freight gauges have the schraeder valve at the gauge head end, the schraeder valve should be at the cylinder end of the hose.

If your gauge is configured this way, it will read way lower compared to the real result..

Always, always, always, compare an unknown gauge, even if new, directly with a known good gauge before you can trust it..

 

[Sportster-2001-951C-Stock]

Even if it was incorrect a 30 psi difference isn't good.

That's certainly true, 30psi is unacceptable and indicative of a problem. But if that schraeder is at the gauge head then all bets are off with that gauge, go get your money back or use the hose from your old gauge if it will fit.

Sometimes those schraeder valves will leak and need to be replaced, they get dirt in them or whatever, you can get the special replacement schraeder valve made for compression gauges.

 

[laptop4079]

UPDATE TIME, Sorry it took so long I had to call in the neighbors and even my father trying to figure out the least destructive way to pull the head off with 3 bolts acting like guide pins cementing it together. After proving the air hammer the best tool to own JeremyD was correct there was a lot of sadness in there! My next question is what caused this and where do I get new jugs from because all I see are cylinder exchange programs and these are a little too far gone

 

[Sportster-2001-951C-Stock]

Contact the exchange guy and explain, I've been shocked by getting full core on remans that had blown up, maybe you have already.

 

[mikidymac]

Your crank is probably bad also with cylinders that bad.