Hi, I'm new here. I have a 97 Trail boss 250, it has been sitting up for a couple years. I wanted to get it running again. I took the carb and cleaned it out very good, actually I've done this 3 times now. Cleaned the gas tank, and changed the fuel and oil filters. Also, had to free up the throttle cable but got it freed up also. Here is the problem, when you start it, it starts right up. But then start idleing higher and then gradually gaining more RPM on it own. I've checked everything. Checked for air leaks in the rubber boots and everything. You can put your hand over the hole on the carb and it will idle back down......Any suggestions at all???

It does this with and without the air filter on it. Its not idleing high, its gaining RPM like you are gradually pressing the throttle....Thanks for the help in advance.

 

have you checked your crank seals for air leaks

 

Well somebody had told me that but I was told by the dealership that it wouldn't start if it was crank seal. How do I check them? And I'll do it..... Also, how do I get to them to change them? Is there a website or something to look at....

 

I don't know if this will help or is even the problem... But I have a 90 trail boss 250 and it did the same thing... My battery was low so I charged it and it stopped, a few weeks later it started again and the batterry was low again too... I replaced the battery and hasn't done it since... Just something to check....

 

are you the throttle cable is completely free and that the idle is turnes in and the air screw is set right. make sure the choke lever is aslo not sticking. if all these things are fine, then i would say you might have a air leak. some people use starting fluid to spray behind the primary clutch where the crank seal is, but its highly dangous from it might cause a fire. best thing to do is a leak down test on the engine to see if its actually got a air leak. way safer as well.

 

Well the Throttle cable does seem stiff but would this make it raise RPM like that? Without me pressing the throttle... I may have to take it to a shop, I was just hoping I could find the problem myself and save some cash. Its not the battery, I just put a brand new one on it this week.....Any other suggestions?

 

If your left front tire has more air pressure than the right rear tire of your neigbhors quad that can cause the problem also.

 

How far down should the plunger like thing in the carb go down? The part the throttle cable attaches to? Should it rest in that indention in the bottom of the carb? I have notice mine is up about 1/8-1/4". Could this be the problem?

 

By "plunger like thing" I am assuming you mean the carb slide. The slide should rest in that indentation without throttle. You either installed the slide backwards when you cleaned the carb, or you need to adjust your throttle cable where it meets the carb. There is a jam nut where the cable meets the carb, loosen the jam nut, and screw the adjuster in, it should start lowering the slide.

 

Yes thats what I mean. Its not in backward, I know that much because there is a groove in it so it can only go in one way. I do however know, that is doesn't rest in the groove on the bottom of the carb. So that has got to be the problem. I will work on it tomorrow and let yall know how it goes. Thanks for the help.

Also where is the best place to get some performance stuff for this thing, exhaust mainly...