Super Jet Runaway Superjet

[johnknwd]

So I think I just damaged my Superjet motor but I'm not sure what to do for my next step. I just replaced everything on the electrical system on my ski, Stator, cdi, coils from a no spark situation. I fired up the ski in my garage last night and it ran away. Pulled lanyard, spark plug wires and wouldn't stop. It was dieseling. I pulled the ski out of the garage because I didn't want to have it explode in the garage and it eventually stopped, probably 1 minute of high rpms until it died. After reading the x I should have just held it wide open but it was a bit hectic when this happened and I panicked. It's a single carb 701 motor that was running fine until the no spark situation.

Motor didn't sieze and turns over, I still have spark but I'm afraid to start it again because I don't want to grenade my motor.

I know I'm an idiot for not running it under load but I was excited to see it had spark again. There was definitely air in the fuel lines that I think caused this, haven't ever taken apart the motor or removed carbs.

What do you guys think about either throwing it in the water and giving it hell? Or should I take it apart and look for damage? My plan is to get a jetmaniac top end this winter anyways.

Thanks for your comments, I wouldn't have attempted anything without this forum.

 

[SRQski]

You're probably fine, if you had the carb off - dbl check for gasket issues that could cause an air leak in addition to getting the air out of the fuel lines.

Lean runaway is scary the first time it happens and can induce a panic feeling! Options to stop it: choke it or flood it. You can either plug the exhaust w a rag or hold throttle wide open and use the choke.

For air in fuel lines or reinstalling fuel system anytime: an easy way to prime fuel pump and lines is to take the return line off the fuel pickup and remove the fuel vent check valve. Blow into fuel vent hose, create positive pressure in the tank and hold it until you have good fuel coming out of the return line (hold a glass jar or something under it to catch fuel). Hook lines back up and fire it up.

Sent from my SM-G960U using Tapatalk

 

[johnknwd]

Thanks for the info, machine started right up and I have been running it all weekend. Probably 6 tanks of fuel through it. Couldn't do it without the help of the forum. Hopefully I'll be able to repay the favor when I learn more.

 

[yamaharider85]

When that happened to my Raider 701 62T I rebuilt the carbs with genuine Mikuni rebuilt kit also put new float bowl valve and seats. Everything has been fine for seasons. It sounded like the same exact symptoms you had. What was the issue?

 

[johnknwd]

I think it was a combination of no prime in the fuel lines and me trying to get it to kick over by putting gas in the carbs. Did it 3-4 times and then it happened. I also noticed a little crack in my fuel filter and the lines were bleeding just a little bit. The plugs were hot and so was the combination chamber and that created the dieseling of the plugs (the fuel was igniting without spark and just compression and heat)

The next time I manually primed the lines by pressuring the tank like the reply on the thread and I was golden. Fuel filter to carb and lines were replaced also.

 

[yamaharider85]

Glad it worked out for you. I thought my motor was going to spin to its death. First carb rebuild ever on the raider and Ive had it since 2000. Hopefully its good for another 18.

 

[johnknwd]

Yeah it was terrifying, I was throwing gas cans out of the garage and dragged the machine outside, stood far away waiting for my dreams to explode. Motor will be sent out this fall to rebuild as a precaution anyways. I'm sure it caused damage somewhere and I don't want to be stranded out on the water. Plus it never hurts to have a bit more brap.