If you’re unsure, pre mix another tank. It won’t hurt anything
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GTS cavitation?
- Thread starter Gwstaudy
- Start date
So when I posted that other message I had the ski in the water it was running good but it would stall sometimes and would be hard starting but then other times it would start first crank. I went on an oil run because the light came on and it took about an hour. I came back and filled it up and went out but it wasn’t running right. It was like maxing out at a lower rpm as if it were cavitating but it wasn’t. Randomly it would pick up and get power and be able to go faster. If I blipped the throttle a lot it would get up in plane and I could go like I was before. It would run good till I stopped and when I went to go again I had to do the same to get up and going. When it was up and I was moving fast it seemed like it would randomly give me the real power it should have then it would drop and have less power.
Sounds to me like it’s running rich on the low end circuit, could try turning the low speed in 1/8 turn. Easy to put the voltmeter on the battery and run the machine to 4500 rpm to see if it is a rectifier. With it randomly losing power at high speeds, I’m not sure. I can’t remember if you rebuilt the fuel system or not? But I would go through the fuel system, if you haven’t already. Don’t keep driving it, in this condition though
That would cause it to be maxing out at a low rpm and speed?
Correct me if I’m wrong, I read it as you were having trouble getting it up to speed but if you feathered the throttle you could eventually get it to go good? If I read that right that sounds like the low speed circuit is a little rich. You are saying that at higher speeds it would go good and then drop and have less power? To me that sounds like your not getting enough fuel at higher rpm’s. Did you rebuild the carb with a good kit and do the testing on it? Good black fuel rated fuel lines? New fuel selector valve from reputable company not Amazon? Or leak test it? Did you leak test the crankcase after rebuild? Definitely like to see what others think, but it sounds like fuel/air to me
Yeah if I just got on it and pulled the throttle it would go but max out at a low speed and not go any faster and more throttle wouldn’t help. The carb has been completely rebuilt with good parts and tested. The whole fuel system has also been rebuilt. I never leak tested the crankcase. It gets up after feathering the throttle but it’s iffy. Sometimes it works right away and sometimes it takes more time. When up on plane and cruising it seems like it’ll suddenly get more power without accelerating and then it goes back to how it was after a bit. It’s very random.
Are you saying the engine revs out fine, but you’re just not moving like you should be?
No it’ll stop revving up even with more throttle like it’s maxing out and if you feather it it’ll start going normal again.
Check the regulator.rectifier, but sounds like a fuel issue. Where did you buy the carb kit from? Don’t think it’s your issue, but have a 1 minute ride with the seat off and look for exhaust leaks. You’re not running any aftermarket fuel filters or air filters?
Not sure where I got my carb kit but I’m certain it was an OEM Mikuni kit. How do I check the regulator and rectifier? I took the seat off while riding and didn’t notice any exhaust leaks. It has no aftermarket parts besides the impeller.
Just turn your multimeter to DCV, put the leads on the battery , check volts at rest, start the ski, see what they are at idle, I believe 12.8 ish to around 13.5 ish at idle and then see what you get at roughly 4500rpm, should be roughly 13.5 ish to 14.5 ish.
I don’t have a tachometer but I’ll do my best.
It doesn’t need to be precise at all, just as long as rpm’s are increased and volts go up but stay in correct range
Something I forgot was that it would lose power when I was varying throttle and feel like it was going to stall out but if I feathered the throttle I could keep it alive and it would get power back. It seemed very random so I’m not sure if that means anything. I was thinking it had to do with the extra oil it’s running but I have no clue.
It has nothing to do with the extra oil, I’ve done it many many times with seadoo’s and snowmobiles where I’ve ran the oil injector toon and pre mix at the same time, never even fouled a plug. The feathering of the throttle to bring it back sounds like fuel. Yes, you can remove the red wire from the rectifier and if it solves your issue then you found a problem, just keep in mind that your battery will not be charging while that red wire is off so keep your ride short and start out with a fully charged good battery. Keep the ride to 10 minutes or less. You can also test the rectifier using the method I mentioned in previous post using a multimeter. Yes, there are testing procedures for the stator laid out in the manual where you will Ohm certain combination of wires coming from the stator. I’ve tested the stator in my ATV in this manner and have also tested the ACV coming from the stator in the ATV, I would think they would be similar on a Seadoo, but I’m not sure if they test is mentioned in the manual or not.
I just chased down a rich condition that ended up being a bad spark plug boot. This is the second time that it has happened to me where a spark plug boot was causing a rich bog. I could feather the throttle and get it to rev up and run so I was convinced that it was fuel related...It kicked my A$$ twice.
I had it out on the water and I found out it’s gotta be a fuel issue. If I adjust the fuel shut off it runs differently. If I turn it to the off it’ll just go until it obviously runs the gas out of the line. If I turn it past the on it works fine so that’s sorted. Must just be a cheap selector. My new issue is that I had it running great no problems then when I went out it started dying on me. I get up on throttle and it’ll hold it for a bit then it seems like it runs the gas out of the line and isn’t picking enough up out of the tank. It’ll start right back up and go again but it won’t stay at half throttle or above. I had someone suggest there could be a hole in the baffles and as it’s using gas it sucks air instead?
Not sure where your at? Did you get the wear ring changed to a good OEM one? You mentioned a cheap fuel selector valve that was giving you issues? You can bypass the selector valve and fuel filter if you think they are giving you problems. Not sure if you have rebuilt the carbs after the engine rebuild but if you haven’t, I would. If you have compression and spark? Then just go through the fuel system, back to OEM carb rebuild kits from OSD, no Amazon or eBay junk so your not chasing your tail, black automotive fuel lines, follow the carb rebuild thread, set screws to factory settings and you should be good to go.
Yeah I bought a new pump housing and threw my solas impeller in it and it has perfect clearance. I know the jet pump isn’t the problem because it’s perfectly capable of running good. It does seem to get up and go fine when I put the selector to the correct spot. It just keeps stalling out after 5-10 seconds at around half throttle. It’s like it runs the gas out of the lines then it’s not getting enough. I have been through the carb since the rebuild so it should be good. Everything is new in the fuel system.
If you use a good polyurethane fuel line you can see if the fuel delivery is working properly. If the fuel selector is leaking air into it you will see that there is no air going into the selector, but there is air coming out of it...bad selector. Same for the water separator. if the O-ring is bad bubbles will tell you in 10 seconds that you need an O-ring. No replacing perfectly good parts just because somebody said it was a good idea. Even if the fuel line is leaking air in...easy trouble shoot. If you don't have clear lines you first have to recognize that you have a problem before you blow up the engine, then you have to pressure test the system and spray soap and watch for bubbles outside the fuel lines. There may be better fuel line, but the benefits out weigh the risk.
I recommend the rubber/nitrile fuel line because I’ve seen many posts stating that the polyurethane fuel line gets hard and brittle in a short time period, I’ve heard 2 weeks, I’ve heard a year, I’m sure it depends on where it’s purchased but either way your not going to get anywhere near the lifespan. You don’t have to just replace parts, you can test the selector valves and fuel filters with vacuum. The black automotive fuel line isn’t going to leak at the fittings so no need to have to look for air bubbles
How do you
How do you know that you don't have leaks? You could have a small leak in an O-ring and not even know it for a year. Not all clear fuel line is the same. There is Tygon, polyurethane and knock offs of both I think I have tried them all. I am no Seadoo whisper, I need help with tuning these things. On my first experience with replacing fuel line I went to an automotive parts store and bought rubber fuel line. I don't think it is Nitril...just rubber. I am still running it, but I don't know if it leaks, because I cant see if it leaks. I went to a Seadoo Tech and he said "what is that?" he acted like he had never seen traditional rubber fuel line. He used yellow Tygon fuel line. Next ski I bought yellow but I think I got the knock off brand. It got cloudy and hard, but not brittle...I can clamp it with out damage. I am still running it with no leaks. Next I bought blue from a Different Seadoo tech. It is performing about like the yellow knock off, but not cloudy. It had 1 leak. I saw it clipped the end off new zip ties...easy fix. since then I have bought 2 different blue lines one is softer than I like. but working fine. The other is new to me, but looks like the best that I have found so far. It is Lamons Corporation Polyurethane. The bottom line is that the worst clear line only takes about 10 second to diagnose an air leak before the pump. If there is no air going into the carbs, everything up to the tank is good to go.
Been doing this for over 30 years so take it for what it is worth.
I have seen countless engines seized from the crap clear fuel line. Yes, when new you can see air leaks. As it ages and gets hard it always develops air leaks or it breaks off from the engine vibrations. But nobody checks for leaks after they install it so when it gets hard in a year and starts pulling air up under the dash on the fuel selector where you can't see it then on a WOT run across the lake your engine seizes.
The black fuel line doesn't get hard and makes a better seal on all the fittings, it just doesn't leak if you install it correctly with good quality zipties. You can also use your pop-off tester to put a few psi into the fuel system and see if the pressure drops to check for leaks so you can verify your fuel selector and fuel strainer are not bad along with your connections.
Bottom line all the clear hose will get brittle, hard and eventually leak. You could use genuine Tygon hose but you are just as good off with standard black automotive line. If you want the best of the best then use Motion Pro Premium Fuel Hose. It is what Yamaha uses on their watercraft and I have some that is 35 years old and still soft and pliable.
I have seen countless engines seized from the crap clear fuel line. Yes, when new you can see air leaks. As it ages and gets hard it always develops air leaks or it breaks off from the engine vibrations. But nobody checks for leaks after they install it so when it gets hard in a year and starts pulling air up under the dash on the fuel selector where you can't see it then on a WOT run across the lake your engine seizes.
The black fuel line doesn't get hard and makes a better seal on all the fittings, it just doesn't leak if you install it correctly with good quality zipties. You can also use your pop-off tester to put a few psi into the fuel system and see if the pressure drops to check for leaks so you can verify your fuel selector and fuel strainer are not bad along with your connections.
Bottom line all the clear hose will get brittle, hard and eventually leak. You could use genuine Tygon hose but you are just as good off with standard black automotive line. If you want the best of the best then use Motion Pro Premium Fuel Hose. It is what Yamaha uses on their watercraft and I have some that is 35 years old and still soft and pliable.
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