Ever since I bought my quad when I start it doesnt seem to want to stay running when cold. I have to constantly play w/ the throttle or it will stall out. I have also played with the choke an awful lot, it helps but even w/ it choked it will still die out more often then not if not payed attention too. Since I did buy it new in the winter I thought it was just because it was cold outside and the engine needed to warm up. My brother has on 01 honda foreman and it seems to idle just fine right off the first push of the starter, few time have I seen him push it more then twice. I also rarely see him open up the choke either. My question is, is there somethign wrong w/ my quad? Or do yamahas have a problem idling? By the way, it does idle perfectly after I have already taken it for a ride. Turn it off to take a drink or whatever, starts back up and idles fine in neutral. But just seems to be a pain in when starting it up for the first time of the day, or after it has been sitting for a while (cold). It gets embarrising when I have to play w/ the throttle on a brand new quad and a 5 year old honda is just running next to it.... Any ideas?

 

Try backing the fuel screw out about 1 turn and see if that does anything. Sometimes they will idle rough if they're too lean.

 

I don't really see Yamaha quads idling better or worse than other makes in general. One thing you need to realize is that manufacturers are shipping quads leaner and leaner to help meet emissions regulations. Engines like to be a little rich when starting and warming up, so some simple carb tuning may help your cold start problems. I would go up a size on your pilot jet and see if that helps any. Additionally, make sure your quad is getting good fuel flow, has fresh gas, a clean air filter, and throw a new, properly gapped plug in while you are at it. Sometimes you just get a cold blooded beast, and that will add to the character of it, lol. However, tuning can often help out the cold starting problems.

 

It has had its first service and still has the idling problem after new plug and adjusted valves, also I never mentioned this problem. Recon, where might i find the idle screw I'm a mechanical noob, especially when it comes to atv's. I do know I need to buy the service manual.

 

There should be a brass flat-head screw on the bottom of the carburetor.