run away 2 stroke!!!

[3>4]

My 82 250r runs away when I start it. I can't find any air leaks, the reeds look fine and the carb seems ok.

[Bren_downe]

It's either an air leak or it's not getting enough fuel.
Check fuel flow from tank and check float level.
Look up "leak down testers" and make one.
Maybe your crank seals? I'm not sure if that would make it rev out like that…

[threewheelin-feelin]

did you make sure your cable and slide arent binding up?

[Darius1502]

It could be a bunch of things:

- carb slide stuck
- air leak
- not getting enough fuel
- throttle cable binding somewhere so its pulling the slide
- too small a pilot jet (causing a lean condition)
- Yes a dry side crank seal leak (ignition side)

Its scary as hell when they do that. I had a KTM 500 do this...scary when a big two stroke is reving like that and you can't stop it!!

The throttle cable on mine was binding up!

[BOB MARLIN]

The slide in the carb is in backwards ?.

[DohcBikes]

Did you recently mess with it?

How long has it been doing this?

Did it start acting up suddenly, or slowly over time?

What do you mean the carb seems ok?

Check for fuel blockages from the tank all the way to the intake.

[3>4]

I rebuilt the engine. It didn't do it the first few times I started it. It just kept getting worse every time I started it. I am getting fuel in the carb. It will run slow enough if the choke is on. I'm going to spray some WD 40 at it to see if I can find an air leak.

[emmie357]

Did you do a leak down test after rebuilding?

I would start by pulling the carb and checking that the slide goes down all the way... if it does, then do a leak down test.

[3>4]

A leak down test would tell me if I have a leak. But I don't have the equipment to do it.

[emmie357]

You can build one cheap, do a search and you will get a ton of ideas/materials to use.
In the long run it's great to have one on hand. And there is really no substitute.

[DohcBikes]

revving but runs slow enough when choked, its probably lean.

[danbur55]

had same thing after rebuild on polaris 250 trailboss, somehow crank seals did not hold up replaced them again and cured it leakdown test is in order

[atc007]

I think WD will just make it shiny. ? I've never used that method,I do use Ether. But you need to do a real leakdown test,as suggested many times lol

[kbatc]

Pull the bowl check the pilot and float valve especially if you running ethanol fuel probably orange goo in the float bowl limiting gas flow.if not then x2 on the air leak,should be easy problem to solve with right tools..

[3>4]

I traded it for 2 200x's.

[mike m]

I had this problem a couple of years ago on a 84 250r it turned out the base gasket was leaking.