Super Jet 2001 superjet running problem

[gritzke]

my sj ran perfect i took the gas tank and battery out to have the ski wrapped about 3 weeks later i put it back together and went to ride started fine went out about a 100 feet and it died.checked a bunch of things. still died out after 6-7 seconds of running decided to rebuild the carbs, bypassed the fuel switch and ran a direct fuel line from the tank to the back carb, took it out today and still the same thing but if i go wide open throttle and stay open it will run as long as i hold but the second i let off a little it dies out almost like the ignition gets killed i adjusted the low speed needle and high speed to all different settings, i spent all day messing with it, its getting gas so im assuming thats not the problem now im thinking electrical has anyone had a problem like this,thanks for any advise i know the msds have problems but its a stock cdi factory b pipe ada head any suggestions Ive looked thru all the threads and read anything even somewhat close but no solutions

 

[munki63]

Is it hard to start at all?
First check your filters inside your carbs...even tho you just rebuilt them, The same thing happened to me and that was the problem, since I had just rebuilt the carbs I didnt think it was possible, I would also suggest a inline fuel filter outside your carbs,When you rebuilt your carbs did you replace the spring that came with the rebuild kit? Also check that your fuel pickups aren't bent.

Second did you fiddle with the exhaust at all? you might have a leak which would choke out your motor because of the lack of oxygen, take your ski for a rip with the hood off, If the problem goes away thats your problem

Start simple....doesnt sound like an electrical issue

 

[gritzke]

It dies with and with out the lid on today was glassy so I did actually go out but it died right at about 40 ft and I did change the spring to the most similar spring but I'll check the filters again and I checked the pick ups and they checked out solid it just doesn't make sence you can ride wide open but the second you let off it dies that's why I think it's electrical cause it's getting gas

 

[munki63]

When you changed your spring you probably changed your pop-off pressure start by putting the original spring in, If you still have your heat sensor installed? It could be shot?

 

[Crab]

sounds like low speed circut in the carbs, I see this all the time if you really don't know how to check/rebuild them properly. Often overlooked is a worn throttle blade, it will also cause tuning troubles and engine run away. Checking pop off is mandatory if you want it to run right, good luck.

 

[gritzke]

how do you check pop off, i dont even know what pop off is

 

[gritzke]

and the heat sensor is taken off already cause it has a ada head no sensor on it

 

[munki63]

It might be your CDI in your Superjet manual it tells you how to check your CDI to see if its working 100%
Replace your springs, I understand pop-off but not enough to fully explain, you will have to use the search button for that one

 

[onedumbtrucker]

Have you done a compression test of both cylinders? I had a similar problem with a 550 Kawi after I partially cold seized my rear piston. I could keep the thing running at full throttle but it felt weak and when I let off it would die when I was in the water, out of the water it seemed to run much more normal. I did a compression test and found I was about 40psi low on the rear cylinder.

 

[icecoled007]

Check your external fuel filter? Are you using good fuel? I would double check those carbs and put the old springs back in.

 

[D-Roc]

you probably got the pop off wrong and the fuel timing is not working in lower rpms. put your original springs back in.