Hey all Ive been searching google for over an hour with no luck and was hoping someone on here could help. I have a 89 Lt250s and am having trouble with a high idle when the choke is off. I've cleaned the carb numerous times and dicovered that a vent line that goes to the top of the carb goes underneath the fuel tank and is connected to nothing at all. I would think it should link up to either the fuel cap or maybe had a breather on it. I also saw the line that goes from the air box that connects to the crankcase then T's off to nothing at all as well. Does anyone have a diagram or possibly know where these hoses should go. PS I don't have a petcock that can accept a vent line only a fuel line. Thanks a million

 

I had a very similar problem but on an '87 LT250R. Ran great with choke, but shortly after you turn the choke off, idle starts to climb, climb, climb (if you've ever forgot to turn your fuel petcock on, a similar situation happens). Mine went about 85-90% throttle for a solid 3-4 seconds in neutral in my garage. I freaked! The kill switch didn't shut it off. Pulling the sparkplug coil didn't even shut it off! She was hot, had compression, and was leaning out. I had to drop it in 1st gear with the brakes on and stall it out. Broke my water pump gear shaft from the sudden stoppage. But I was lucky I didn't throw a rod or something far worse. I found 5 leaks and replaced the crank seals and cleaned up some gasket surfaces. Now the high idle is gone and it consistently kicks over 2-3 kicks. Plus 165# of compression helps, too.

The choke is compensating for the air leak by blocking (choking) off carb air and providing a rich condition. As soon as you turn the choke off, you get leaner.

The high idle is probably due to something else. Have your performed a leakdown test on your LT? If not, do it. Especially if you bought a rig from a stranger and/or the rig has been sitting for a while. These things are 20+ years old, so stuff wears out and most of the time rigs get sold off before the preventative maintenance is done. Costs like $20 to make a leak-tester. Search this site and Everything2Stroke.com and SuzukiATVForums.com for "high idle" or "leakdown". Probably crank seals, but could be a top end gasket or something simple.

Might as well pull your carb, too, to check the jet #'s and make sure your floats aren't sticking + are set to spec. But do the leakdown test first.