I've seen this complaint before......my son's raptor 50 starts and runs at full choke but then stalls out when i shut the choke off. Probably a clogged carb.....does anyone have any quick easy suggestions to try and clean out the carb? maybe without having to take it apart? Maybe using some type of carb cleaner?

Also, what is the little brass adjustment piece (a small circle with a screwdriver slot in the middle and three tick marks 120 deg apart) on teh right side of the carb....is that idle adjustment?

 

Classic symptoms of a plugged pilot jet. No spray is gonna do it, you need to remove the pilot jet, and replace it if the center hole wont uncog. The hole is very tiny on the jet, and its almost always the first thing to clog up in the carb. Pilot jets are about 3 bucks at the dealership.
Just before shutting off the motor after every use....turn the gas to off, and let it idle til it dies. This will leave the float bowl dry, and will prevent the pilot jet from plugging in the future. Or you can just open the drain screw on the bottom of the float bowl and that will accomplish the same thing.

 

Thanks buddy....that seems to have done the trick. I took apart the carb today, took out the pilot jet, couldn't see through it, so i cleaned it out with a needle. Then, after getting it all back together, it started and stayed running with choke off. Thanks again!

Any idea how the idel can be adjusted? Is it that little silver set screw on the left side of the carb? It didn't seem to do too much.

 

I realize this is a 5yo thread, but it is my situation exactly so why reinvent the wheel.

However, when I went to my local Yamaha dealer, he sold me Mikuni needles rather than Yamaha branded ones but they are totally different, threads and all. Did I misread that the 50 has a Mikuni carb, and if so, what make is it so I can get the correct jets?

Thanks.