Super Jet SN SuperJet 701 Help please!!!! Video inside

[Broha-X-Press]

Im having issues with my SN superjet. It ran great all last summer, then this winter i tore it down and gave it a makeover. So I just finished putting everything back together and getting turf in, and it starts right up but the idle sounds terrible, oily water from the exhaust, and it won't rev at all. I just rebuilt the carb and I put a new starter relay in. Im wondering if something got knocked around or disconnected in the e-box.

In short, I'm stumped and need some help please!
Thanks in advance!

 

[hink320]

Do you have the hose running before you even start it? That could be your problem, you should start it first then turn on the water, if you turn on the water first you'll fill your motor with water.

 

[Little_Franny]

Almost sounds like a run away due to an air leak.

What exactly did you take apart when you did the "makeover"?

What parts did you replace when you rebuilt the carb?

Did you count your high and low speed screws when you disassembled and set them back where they were?

 

[Little_Franny]

Hink has a good point, didn't catch that

 

[Broha-X-Press]

The "winter makeover" consisted of pulling the motor, fuel tank, water box etc. to clean, paint the engine bay, as well as sand/awl grip the whole ski. As far as the motor goes, I didn't take anything apart because it was running fine, so there was no need to.

Rebuilding the carb was the most mechanical thing I've done to the ski which included a genuine parts mikuni kit. So basically all gaskets besides hard parts.

Yes the water was on before starting the ski. I wasn't aware I could pump water into the ski if it was left on without running it. My other question with the water is I may have the water lines mixed up. I have to assume that if water was run in the wrong direction that it would effect performance.

Thanks for some insight on this. Im new the jet ski world but in my mind, working on things is that only way to learn fully how they work.

 

[Little_Franny]

Well let's start with pulling the plugs, see if there is any moisture on them.

As for cooling lines being wrong, you can overheat your engine if hooked up wrong, did you attempt to ride the ski after the makeover or just run it on the stand?

 

[Broha-X-Press]

It's just been running on the stand. I'll get plugs pulled tomorrow and check again but I did check them when this all started "previous to rebuilding the carb" and they seemed normal.

As far as cooling goes, the exhaust stayed plenty cool, as did the cylinders. I've been doing as much research as i could to try in find a cause and another thing i've heard it could be is the needle and seat. Those were not replaced while rebuilding the carb because they didn't come with a basic gasket kit available from the local store "who was not very helpful with stand up's or yamahas at all".

I know i should order/make a pop-off gauge to check that for sure. I've heard if the seat is bad, it's basically dumping fuel into the cylinder.

 

[Little_Franny]

What concerns me is the hose running while the engine is off in the video. Pull the plugs, see if there is moisture, if there is moisture on the plugs leave plugs out and crank engine to see if you get water out of the cylinders.

 

[Broha-X-Press]

hey so just an update - got the plugs pulled, they look normal (no moisture). Duga deeper and removed reeds to check in the crank case and there was nothing unusual in there. All i found was what looked to be oily gas, i.e mixed gas which still leads me to believe it's in the needle and seat.

I downloaded the mikuni manual and reset my jetting to normal settings. Somehow the jets were almost a whole turn open from "stock" settings, thought the entire motor is still stock!

I'm gonna go ahead and order a new needle and seat, as well as a pop off gauge. If thats not it then i don't really know where to go from there other than a full rebuild, which I don't want to have to do.

 

[Mike W]

My money is on the needle and seat. Set the screws to the stock settings and I bet you will be good to go.

 

[CRJ]

well for one its not running on both cylinders.
secondly since the throttle has no effect on the running speed your issue is in the e-box.

it sounds like you have things hooked up wrong in the ebox, and the ski thinks its on rev limiter. since you said you replaced the starter solenoid, it wouldn't surprise me if something got disconnected or connected wrong.

to test the one cylinder theory, remove the front plug boot and try to start it. then try it with the rear plug boot off and the front boot back on. ill bet ya it wont start in one of those configurations.

example of what it should idle like.

 

[Broha-X-Press]

thanks for the heads up. I obviously know what it should sound like. I pulled the e-box apart again and everything is connected correctly. I even pulled the connections apart and gave them a scuff with light sandpaper so everything was getting good electrical flow. Ski started on both configurations of one plug off. What in the e-box would i look to replace at this point? CDI? i'm not entirely sure about electrical components, not to mention i'm getting pretty bummed with this thing since summer is winding to a close.