Super Jet how do i tune my sj carb so i dont blow up a new motor

[DezKnotz]

ok i have a 09 sj with one season on it and i just did a b pipe and ada head to it with the jet size that factory pipe said to. when i got done the ski was loading up so i turned in the low screw a little at a time till it ran better, a total of two turns total and its much better but still a little of but im afraid to fry the motor. what should i set the high and low screws on the carb at so it will run good while keeping my motor safe

 

[Matt_E]

You should hook up a tach to tune the high speed screw.
The low speed should be tuned at idle on the trailer. Adjust the idle stop screw so that the motor won't die.
Then adjust the low speed screw until you get the highest sustained idle.

 

[D-Roc]

leaning out those screws and making it run better is an indication of what you need to do with the internal jets or pop-off to get the correct tuning. Do you have the oem flame arrestor and screens/choke plates all installed still? that can produce a jetting or pop-off adjustment also.

 

[DezKnotz]

just the choke still, what should the lows normally be set at ?

 

[D-Roc]

like matte said. every ones are different because if you turn your idle set screw up or down to raise or lower idle rpms, you would need to adjust the low screws for the smoothest idle. if you got it bang on, the ski should idle perfect forever and you can kill the motor and restart without throttle. so when tuning i always start at one out on all screws.

 

[Tyler Zane]

having it run good on the trailer and run good on water do not coincide. i learned this the hard way. upon landing in the surf i would get a bad bog (ski ran flawlessly on trailer), all i had to do was lean out the low speeds 1/8th turn (which made it sound funny on the trailer). tuning on the trailer only gets you close, finally tuning should be done on the water. before yall start throwing rocks at me for complicating this for the op, i wish i would of known it sooner when i tuned for the first time.

also, im just the middle man, all this comes from Art at jetworks.

 

[txsuperjetfreak96]

yeah i did all of mine while rideing, was a pain in the ass, but i got it, I installed a primer on my ski, i never have to use it, my ski sat all winter long and it fired right up without primeing it.

 

[txsuperjetfreak96]

oh and also check your plugs and make sure your not running too lean, i Believe they need to b a little wet, dont quote me on this what i read in my yamaha service manual

 

[D-Roc]

i think matte meant on the trailer in the water under load to set the idle/low speed screw.

 

[Matt_E]

Yes, I did.

 

[txsuperjetfreak96]

ok i have a question in my yamaha service manual it says, 1 1/4(+1/4) whats that mean exactly. on needle adjustments

 

[tor*p*do]

ok i have a question in my yamaha service manual it says, 1 1/4(+1/4) whats that mean exactly. on needle adjustments

'

that means 1.25 to 1.5 complete turns or 450 to 540 degrees of rotation
ignore the service manual now that you have a bpipe and bumped the compression
here is a good source of carb setup info: http://www.x-h2o.com/threads/19403-Carburetor-(specs)-Database-SuperJet-and-Blaster-1&highlight=database

 

[txsuperjetfreak96]

yeah i didnt use the service manual just noticed it. i was curious

 

[kevbo]

Idle mixture needs to be rich of peak on the trailer for best response. He needs to get some experience tuning a leaf blower or model airplane engine before moving on to something as costly as a jetski. Better stick with a leaf blower since the model engine can cut your fingers off.