Super Jet Runs like crap after 10 minutes. Stator? CDI?

[ksarge91]

So I'm determined to get this thing running good. I feel like I'm so close.

Last season, my superjet would run great for 10 minutes, once the motor got hot it would start to run like chit. It wouldn't go into limp mode, it would just only run about a quarter to half throttle. After a few minutes of it running like chit I could hammer on it and it would get back up to speed, then the same thing would happen five minutes later. I have a few hypothesis'....

Did away with the temp sensor. Still runs like a turd

Maybe a bad stator or CDI? I'm not that familiar with stators and CDI's but can anyone give me an idea of the symptoms that come about when you're stator or CDI start to go?

Maybe I have an exhaust leak and once the engine compartment fills up with fumes the motor starts to inhale them and choke??? I guess the only way to tell this is to ride it with the hood off for 20 minutes or so.

Any ideas?

Thanks

-Kevin

 

[XJCrawler]

Hows your oneway valve on the gas tank?

 

[ksarge91]

Hows your oneway valve on the gas tank?

I honestly don't know, I'll check it out thanks. You think a blockage could cause something like this?

 

[XJCrawler]

I honestly don't know, I'll check it out thanks. You think a blockage could cause something like this?

If the valve isn't working it will let air into you tank, not allowing it to pressurize. Blow into the valve, it should only let you blow one way. If its failed it can cause your ski to run bad after a little bit of riding

 

[ChrisFiore15]

^^Great idea!

 

[ksarge91]

Good call. I thought the tank not being pressurized would have more immediate effects but now that you mention it that does make sense. Thanks for your help I'll check it out tomorrow.

Chris I saw your advice on the other forum I'm gonna give that a shot tomorrow as well

Thanks guys

-Kevin

 

[tom21]

coils act up as they heat up. wires that are old will short in salt water when wet also.

 

[Pablo]

I had same issue a few years ago...I was running a TL and it died. I had to go back to my oem electrics that I had never run on that ski. It ran great for 10 minutes or so and it would eventually just turn into a dog. I replaced coil/plugs and in the end it turned out to be a ty cdi. Weird scenario but swapping the cdi cleaned it up. I'd verify tank vent first and all connects are clean and secure as well.

 

[flipside]

been having same kind of issue lately as well, stator looks golden, new coil.. gonna try the simple easy fix!

 

[N3vrSat1sfied]

could be a heat soaked stator (works great until hot). Had that happen to me before.

 

[OCD Solutions]

I had a similar issue with my wife's 96 SJ but hers wouldn't run at all. I swapped out the riva cdi for a new enhancer and that solved it for about 2 rides and it started doing it again. I ended up sending the stator to JSS and it has run great ever since.

An intermittent cdi is a bitch to track down if you don't have a known good spare to swap out with. Unless it fails outright, the symptoms can appear to be many different things and have you chasing your tail for weeks. If you can swing it, borrow or buy a good one for testing. Even an old stocker will work for testing.

 

[ksarge91]

Think I may have figured it out

I have don't have a fuel selector or an external fuel fill. I run my my single fuel line from the front of my tank where the fuel fill usually goes to the carbs, and a return line back to the left nipple on the top of the tank. On the right nipple, I run a line to the stock water separator mounted to the left side of the ski, then to a check valve, then up the pole.

If I pull the breather line off the left nipple, I can easily blow out the water separator. This would be keeping the tank from staying pressurized.

I should have had the check valve in between the tank and the water separator, not in between the water separator and the line going up the pole.

Sound about right?

 

[BruceSki]

Throw that water seperator out. Run the breather on an inch or so of hose right off the tank.

 

[ksarge91]

That's what I'm planning on doing, just running the check valve

 

[wanderer1]

Not sure if you checked yet but is there any water in the tank? Is your fuel cap cracked? Carbs could pick up water,run bad, clear up run good. Cracked plastic cap could be letting air and water in. Happened on my Kawis all the time. Billet fuel caps and inlet tubes from then on.

 

[BruceSki]

Like this

 

[ksarge91]

Like this

That's exactly what I'm planning on doing. If that doesn't work it's back to square one. It literally runs perfect for up to 10 minutes then turns into a dog

 

[BruceSki]

after that its cdi or stator.

Do you have plug boots that are removable and replaceable? Trim back your wires an inch or two now also if you do. Although that usually doesn't cause the problem you are experiencing intermittently like this. Its usually running good or running like crap. No switching back and forth.

 

[Robnobnorb]

Hi guys any luck with this one in the end!? Having the same issue on mine at the moment runs ok for a wile then after 10 mins runs soo bad have to litterally ride on knees only just fast enough to stay up then it kicks back to life then away for another 10 mins!
Problem is we get such a short summer in the uk and its now going and my ski has been playing up most of it!!!


Need help!!!

 

[XJCrawler]

Hi guys any luck with this one in the end!? Having the same issue on mine at the moment runs ok for a wile then after 10 mins runs soo bad have to litterally ride on knees only just fast enough to stay up then it kicks back to life then away for another 10 mins!
Problem is we get such a short summer in the uk and its now going and my ski has been playing up most of it!!!


Need help!!!

What have you checked so far?