04 will not idle.

First off, I'm a two stroke guy, forgive me!! So I bought a crf250 on a whim, and cause it was a deal. It ran great last time out, but suddenly it will not idle. It runs great, starts easily, and high idle with it choked runs fine. But with the choke off, as soon as I let off the throttle it dies. Its frustrating as hell!! I'm not afraid to rip into the carb, but am looking for guidance before I do. Any input?

Did you try the idle adjustment?

Perhaps the fuel screw has somehow gone out of adjustment.

Is the air filter clean?

Edited by FCR Expert

Sounds like a clogged pilot jet to me.

Definitely to do with the pilot circuit. Ensure the pilot jet and passages are clear, check and reset the fuel screw. Fuel screw position will depend on pilot jet size.

Couple more things to check:

- hot start, check it is not stuck open (or slightly open), or maybe it managed to unscrew itself off a carb a bit, or bad gasket

- the little o-ring on the fuel screw tends to get chewed up and fail.  I'd take the fuel screw out, make sure I fish out the o-ring, spring and washer outta there and blow some compressed air up there.  This can be done without removing the carb

- check all 3 carb boot joints (head to carb to intake) are on tight and clamp screws are tight

- whack the carb with a rubber mallet in case the float got stuck up a bit

- if that doesn't help get the bottom cover off, get the pilot jet out, blow both the pilot jet and the rest of the jets still in the carb plus the fuel screw passage with air real good.  Check that float level is in the ballpark while at it.


That's what I'd do anyway, not really an expert but I had my share of this BS :)

Edited by dakh

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