ditch witch 255 sx

Discussion in 'Mechanic and Repair' started by itteitj, Nov 13, 2005.

  1. itteitj

    itteitj LawnSite Member
    from RI
    Posts: 74

    I originally posted this in irrigation. I was installing last zone yesterday when engine shut down and would not restart. I found a wire in wire harness that was corroded and fixed it but it did not help. I Put a shot of gas down the carburetor and that did not help. I believe it is electrical but don't know what to check. It has an onan 2 cylinder and is an older machine. I have not used it much but did start engine weekly and run it for ten minutes or so each time. It was accidentally stored uncovered for a while and am wondering if magneto got rusty or something like that. It is stopped dead in its tracks, plow down and pipe pulled halfway through zone. Any help would be greatly.

    Tom
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Does it have spark to the plugs ? You say it is a older unit does it have a magneto bolted to the outside of the engine? I wouldn't think rust would cause a problem. I would suggest tracing the kill wire from the unit to the engine and disconnect it, This will tell you if it is the wiring on the unit or a engine ignition problem. I know what kind of bind your in, We have 4 ditch witches in our rental fleet and if they don't run they don't move.
     
  3. itteitj

    itteitj LawnSite Member
    from RI
    Posts: 74

    How can I test the spark to the plugs and where is this kill wire locatedwire
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Remove a plug wire and stick a screwdriver in the end and hold the shank of the driver about a 1/8" from any metal part on the engine and crank it over and watch for a spark to jump from the driver to the engine. Onan had magneto ignitions and battery ingnitions it depends on which you have as to how the kill or shut-down system works. Is there a coil mounted on top of the engine near the intake manifold ? Or is it the mag. style ?
     
  5. itteitj

    itteitj LawnSite Member
    from RI
    Posts: 74

    there is a coil on the top of the engine
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    On the top of the coil there are two small post with wires on them, One has a + sign on it the other a - sign. Use a test light or multimeter and check for battery voltage on the + post with the key on. If present check for voltage on the - post with the key on. If there is voltage through the coil there is a ignition pulse module behind the flywheel that has gone bad. If you have no voltage to the coil then there is a problem with the electrical system on the unit itself. You can remove the wire on the + post and run a jumper wire from the battery to this post to atleast get the unit loaded to take in for repair. If you have voltage on the + post on the coil and no voltage on the - post on the coil I would say the coil is bad.
    You may want to print this out so you can take it to the job site with you to perform the test.
    Hope I didn't loose you here !
     
  7. itteitj

    itteitj LawnSite Member
    from RI
    Posts: 74

    Thanks for the info and I will go and check it now I have a multimeter to do the test. I appreciate your help and I will let you know how it turns out.
    Tom
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Not A Problem, Good luck
     
  9. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    I still think you should check the key switch. Its happeend on two of our ditchwitches, both times it was the keyswitch.
     
  10. itteitj

    itteitj LawnSite Member
    from RI
    Posts: 74

    I will check the key switch as the wiring is old and corroded. I checked the coil as Restrorob suggested with following results. Pos to ground, voltage- Neg to ground, voltage- across coil, voltage. does this mean the thing behind the flywheel should be checked?
     

Share This Page