From Dixie to Exmark

Discussion in 'eXmark' started by taylob, Feb 19, 2003.

  1. taylob

    taylob LawnSite Member
    from Texas
    Messages: 14


    Maybe I can shed a little light on your problem, Manufacturers that provide carbs for engines are under strict guideline to meet epa standards and the carbs are set to run very lean. With this in mind some things can happen. When an engine is running at idle and shut down it draws in more fuel than air and the heat of the engine after running actually increases from heat sink and this can cause an engine to backfire or after fire on shut down. The fuel shut off circuit on carbs works best at half throttle because manufacturers build carbs with the fuel shut off circuit on the the intermediate circuit which occurs at half throttle. When shuttin off at full throttle the engine has to spin down to stop and it draws in fuel during this function and also will cause it to after fire. So the happy medium you might say is that shutting down at mid to half throttle decreases the chances of after fire on shut down. Also, the after fire will not harm the egine. It is just burning excess fuel in the chamber.


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