Super Jet 2007 Superjet dying at high speed

M

MattB

Location
Missouri
I have a 2007 Superjet with blowsion air filters and running amsoil 50:1 premix

Ski had been running strong all summer until this past week when I took it to the river. Ski starts, idles and runs fine until you reach high speeds. When it got to the top end it fell flat.

Talked to a friend who is a jet ski mechanic he said to clean out the carbs. Went ahead and cleaned them out (really dirty) and replaced a couple gaskets and a diaphragm in the rear carb. I tried it out after reinstalling and it ran fine at first, but then went back to falling flat up top. Now when it goes to fall flat if I let off the throttle it will continue running, but if I go to give it throttle again right away it will blubber or just died completely. Don't have immediate access to a compression gauge, but a couple months ago when i bought it they were at 155 each.

I would like to know what I can check and/or do in order to try and get rid of this issue. Any help would be much appreciated
 
Armored snuffy

Armored snuffy

Location
Anchorage AK
This may sound pretty silly but make sure you have enough fuel in the tank. A similar situation happened to me and I overlooked switching it to the reserve setting. Check your fuel lines as well.
 
A

aramis

Location
Rochester, NY
From what you are describing, it sounds like you are not getting enough fuel at full throttle. "Falling flat" sounds like a lean condition to me..."stops so fast it's like you got punched in the stomach" is super lean. So, here's a few common things to check that can lead to that:

- when you were rebuilding the carbs, did you replace the little black filter baskets? (survey says: this is the number one answer)
- while looking in the fuel pump (rear carb), make sure the clear discs about the size of a dime are sealing well (no ripples or wrinkles in them). If so, replace them.
- make sure your one-way valve on the tank is working right. It should let air into the tank, but not let fuel vapors out of the tank. Take it out, blow into it and find out...and make sure to put it back the right way.
- make sure your water separator and vent line (attached to the one-way valve) can breathe...empty the water out of the separator.
- what are your hi-speed adjuster screws set to? Did anybody monkey with them?
- try it again with the on/off/res switch set to reserve, or bypass that selector all together. It can get clogged up badly too and limit fuel flow.
- did you just put in the blowsion air filters (to replace a stock setup)? If so, might need to adjust carbs because you are feeding more air.
 
Last edited:
M

MattB

Location
Missouri
I did not fully replace the small filters in the carb, but I did clean them out as they had some sand in them.

I will try both of your suggestions tomorrow and see what happens.
 
You must log in or register to reply here.
Top Bottom