Honda Spree and Elite 50 Forums

Can bad crank seals cause extremely lean condition? Scooter sat for awhile. Cleaned carb. Fresh fuel. It will start with a small squirt of carb cleaner, then leans out and will die. Fuel bowl has fuel. Somewhat new to 2 strokes, so asking for help. Thanks

ANY air leak will cause a lean condition. Imagine the 2-stroke as basically an air pump. Piston upstroke suck air (and fuel) in...then the downstroke blows air (spent air/fuel) out.

The carburetor regulates the amount of fuel and air to achieve a precise mixture for an optimal running condition. If there is an unregulated amount or air or fuel (a leak)....it will result in a lean (air leak) or rich (excess fuel) condition.

Put gasoline/oil mix in a small oil can with a trigger. Unscrew the cap (the part that the throttle cable runs through) on the top of the carburetor and gently lift it up about 1/8 in, but not enough to pull the slide out of the carburetor. Then squirt 5 pumps of gasoline/oil mix into the top of the carburetor through the 1/8 gap that you created. Then screw the cap back on. Using the throttle on the right grip, open and close the throttle to make sure the cable and slide are still working properly. Then try to start the engine. It should start and run for about 3 seconds until the gasoline you squirted in is used up. If it does, the crank seals are not your problem.

This simple test will answer a lot of questions without taking anything apart, and should be one of the first tests you do when a scooter that hasn't been running for several years won't start.

Thanks for the replies guys. I have done that with pouring in a small amount of gas and it will run for a short time and then die. I read somewhere on here that the air filter assembly has to be on or it will be very lean. Have you experienced that? There isn't an air filter on this scooter. Thanks again.

I guess next thing is to get a air filter assembly! One other question, should the fuel valve bleed off a small amount of vacuum? When testing it with my vacuum pump, the valve works but slowly bleeds down when I stop pulling vacuum on it.

Well, not necessarily. Once the engine is shut off, the vacuum goes away, thus closing the petcock. The petcock would not have to have a built in bleed. That's why I was asking if the petcock has a built in bleed or should it hold vacuum without bleeding off. Thanks.