I just recently put a new engine in my 05 Yamoto. I've tested it out and it runs pretty well. I adjusted the carb to the recommenced settings, and got it to idle. However, sometimes after it idles smoothly for a few minutes, the engine surges. It revs up pretty high, so I turn off the ignition. After a little while of sitting, it starts back up fine.

Is there another adjustment I should be trying???

Thanks
Drew

 

Id look for a vacuum leak first... spraying carb cleaner around the carb/manifolds will let you know.. if it does nothing its ok.. if it dies or rpm increases youve got a leak..

 

Do you have an automatic choke (bystarter valve)?



If you have one of these and it isn't hooked up (or doesn't work) your quad will race and surge at idle after it warms up.

If the connection to the device is intermittent and becomes disconnected, then it will gradually start surging and idling too fast as the bystarter cools and opens the enrichening port back up.

 

It is a manual choke. We can manually adjust it to closed, 1/2 closed, or open. Any other suggestions?

Also, when it does idle down, it idles too low, but we can not see how to adjust the idle.

Any help would be appreciated.