Looking for some help with this weird issue I have going on with my 2003 Polaris trailblazer 250 2cyl. The quad is newer to me but has always had this reverse type of choke thing going on. Idles very high until you pull out the choke a little then the idle comes down and it rides good. I finally got some time to work on it so I turned the choke off (pushed it in) and tried lowering the idle via the screw on side of carb. Nothing happened. Then all of the sudden the motor went crazy and the rpms went to full throttle (at least sounded that way) and wouldn't shut off by the key or on/off switch. Only way I could kill the engine was by pulling the choke out all the way which dropped it down. I've never seen something act this way and was curious if there is some sort of problem known with this quad.

My plan is to tear down the carb and clean it well but any other suggestions on what to check please let me know!

 

A leak down test is the best way to see if you have an air leak,but spray some wd40 around the intake manifold,head and base gasket areas. If the engine rpms drop,you have an air leak,sucking in air,leaning the mixture which can cause an engine to run wild.Crank case seal behind the drive clutch can do the same thing if it's leaking.Make sure the carb is also getting a good supply of fuel,the slide is operating properly and not sticking. Take the carb apart,clean the jets and blow out all openings,plus wouldn't hurt to rebuild the carb with a good Shindy kit.https://www.ebay.com/itm/SHINDY-CARB...!US!-1&vxp=mtr Plenty of videos on this old VM30 Mikuni carb.

 

Thank you very much for the helpful info Old Polaris Tech, I ordered the kit and will start with the carb. Any info on proper way to do leak down test on this machine?

 

Try to spray around the intake manifold,head and base gasket with wd40 if you can first. This may help to find the leak if that's the problem.If you can't with it still running wild,then a simple leak down may pin point it. Here's a couple that show what needs to be done. The kits can be expensive,200 bucks or more,but there are also videos on youtube where people have made their own leak down testers that may help you.

 

Perfect, thank you again!