Super Jet superjet 650 running problems

[alberta guy]

So my 92 superjet 650 is running like crap and I don't know why. It starts and idles fine but when you hit the gas it does not want to rev up. When it does it hits like it has the craziest power band ever. It got a pro tec pipe and hooker 9/15 impeller stock carb and intake. I went and changed the plugs and by looking at them the jetting was spot on with them being that nice brown color. One thing I thought of is when I put it into storage after I bought it this winter after I drained the tank I squirted all the fuel in the lines into the carb with the primer and never started it to cycle it through again. Compression is dead even at 135psi per cylinder (I'm at 2300ft elevation) but I'm going to check it again. I'm mixing my fuel at 40:1. I think my superjet is mad at me because I started that other thread about liking my 550sx more. I'm going to clean my carb and see what kind of spark the plugs have but what else do I check ???

 

[jd91t]

I bet carb orifice/fuel flow woes..

 

[alberta guy]

So I went riding today. I cleaned my carb, checked spark (had nice white spark) checked compression (still dead even at 130) and it ran better for the first ride. But after that it ran the same as before. Played with the idle, high and lo speed screws but I couldn't get it to run any better. What do I do now / check with this ski????

 

[Kohldanielzimmer]

So my 92 superjet 650 is running like crap and I don't know why. It starts and idles fine but when you hit the gas it does not want to rev up. When it does it hits like it has the craziest power band ever. ?

Did you rebuild the carb? What was the jetting when you pulled it apart to clean? When you hit the gas does it just completely fall on its face? Sounds like a possible lean condition.

 

[alberta guy]

No I never rebuilt the carb. 115 main and what ever the pilot was I don't remember. It ran better the first run out then on the second run it was like someone flipped a switch to make it not run as good.

 

[alberta guy]

I figured out my problem. The rear cylinder has 30 psi compression.

 

[XJCrawler]

Wow, hopefully your bottom end is okay

 

[alberta guy]

I don't really care if the bottom end is ok. If I was to rebuild I would just send my motor to sbt and get another one back. And then I would rebuild the whole ski as well. It runs in water and I don't want to take shortcuts and have problems 5 hours after I did a top end. But we are quite slow at work and I rather sell it with a bad top end and take what I could get. I'd rather make money then spend 2 to 3 thousand rebuilding and customizing to my taste. Not to mention I still have the most fun riding my 550.

 

[blake_u]

Yea even if they were at 130 even that'd still be too low. Tear it apart and check everything out. If it runs the bottom end should be okay

 

[blake_u]

If u can just do crank seals and a top end. Unless the cranks destroyed. Even then I'd just get a rebuilt one from jet maniac. I've heard a lot of bad things about sbt