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  1. #1

    Smile hole in center piston in msx 140 Thanks IN ADVANCE

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ID:	233152 I have just in process of rebuilding top end on 2003 msx 140,The center cylinder has an erosion hole all way thru in direct line with injector,The owner says old fuel was run thru it,sine we have no dealer or way to check emm other than to send it off to the people that repair and update mine.Is it possible just the bad fuel caused this???I have always seen bad fuel cause det. and burn thru on exhaust side of piston,however that is on carbed models not on DI models as this any ideasother than fresh fuel run easy and check piston and plugs???Thanks in advance guys>Marvin

  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada
    What do the other two pistons look like? Bad fuel would affect/damage all three cylinders roughly the same.

    Sometimes an individual injector gets clogged up or goes out of calibration (which would cause that cylinder to run lean) but my first suspicion would be that the EMM is not firing that particular injector has strongly as it should be. If the electrical pulse from the EMM to fire the injector is weak, then the fuel delivery will be lean through that injector.

    Pull the injector tip out (gently) and check the screen behind the tip for cleanliness. Also check the electrical contacts in the injector itself and the wire harness connection for dirt, old dielectric grease, damage or weak contact.

    You can either try to monitor that Ficht piston for lean burn without having the EMM serviced, or you can have DFI check it out. Might be cheap insurance to have DFI say it is good (or make it so) rather than burning and fixing another piston.

  3. #3
    K447 is there any service bulletin I should be wary of concerning lean burn.The fuel was very yellow I syphoned out of ski,The other pistons looked ok no erosion yet.I rebuild many twin seadoos that only fry one cylinder due to bad fuel,using single carb but again
    it is definetely detonation hopefully,I'll go real easy and if I notice missing or plug looks off I'll shut her down and send emm off.I should have bought stock in DFI yrs ago,They have treated me very well,done some huge repairs (where half board was cooked and still charged same!!!They must be doing very well,seem like great guys,thanks for your help as always>Marvin

  4. #4

    Join Date
    Aug 2006
    Homer Glen Il.
    fuel pump regulator could have fell off and caused it to loose fuel pressure and go lean

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