SN Superjet Bogging Issues

Hello, I'm having some issues with my 1990 650 Superjet. So here is the background on the ski if this makes any difference... I bought the ski at the beginning of summer. It has a good amount of aftermarket parts on it: Pro-tec head and pipe, Riva flame arrestor, stainless steel prop, and other various mods like rideplate etc... The ski had been sitting for a year.

The initial problem I was having was not very much power and bogging. I replaced the gas, fuel lines, and rebuilt the carb. After that it ran great. Then I ran into the ski going into limp mode, only to realize that the coupler cover was broken off and water was spraying right into the flame arrestor. Got that fixed, and the ski seemed to be good... Until about 20mins into riding it would just start to bog and have really weak power through basically the whole throttle range. This seemed to happen after riding pretty hard and falling pretty good. It would ride like this until I would get it in a straight line and pin it and it would eventually clear up or if it sat not being ridden for a while... The problem was repeatable throughout the weekend. I was thinking I was still having water intrusion problems, but the weird thing was that after having this bog I would pull up to shore and in the hull towards the bottom around the fuel intake manifold there was a greyish slime?? It was like the texture of grease. I found out this is what happens when water mixes with the fuel/oil mixture... So this kind of confused me. So does anyone know if this is still a water intrusion problem, or a possibly something to do with carb tuning? Maybe even bad gaskets for the fuel intake manifolds? Bad reeds? I'm still learning when it comes to these stand ups and engines, so any help would be appreciated! I just want to narrow it down before I start spending more money and tearing stuff apart!

Thanks a lot!
 
Where do you ride? Do you ride on the great lakes or in the ocean? You are experiencing water being sucked through your intake. At least that is what I think, because I've had almost the exact same experience as you.

The SN superjet is a beautiful freeride machine but it's hood design is ridiculous for aggressive riding. Gallons of water are getting in to your engine compartment and bouncing their way in to your intake. Luckily the 650 engine can take it for a while. Do you have a stock flame arrestor? If not, get one. The next step is the SN hood mod. Which is a project I've been waiting to complete since winter as I continue to break other things on the ski. lol.

Electric bilge, stock flame arrestor, and hood mod will fix your problem.
 
I ride fresh water lakes. Yeah the hood mod is next on my list. I just have no experience with fiberglass work... And I'm looking to get a an oem flame arrestor too. I was pretty sure it was water intrusion still, but that white greasy substance is throwing me off. Any ideas on that?
 
I wish I could help you with that however I am a novice and my experience consists of trying to freeride a stock square so that's all I can help you with. you should post a pic of the issue and hopefully someone with the knowledge can point you in the right direction. However chances are it is due to the water going through your engine.
 
Top Bottom