Kawasaki fh500v Governor Prob.

Discussion in 'Mechanic and Repair' started by Mark Brown, Jul 27, 2011.

  1. Mark Brown

    Mark Brown LawnSite Member
    Messages: 14

    My friend has a Kawasaki FH500v motor on a older great dane mower. This spring it had a issue where the cooling fins were very clogged and the motor went into thermal runaway and got very hot and would not run right after that. After reading some posts on this site we found that the plastic parts in governor might have been damaged. Upon cracking open the case it was found that this was the problem, as the plastic and ball bearings were not as they should be, in fact the plastic parts were just black clumps in the bottom of the pan and the bearings were also in the bottom of the pan.

    Replaced the plastic retainer and the 6 bearings that make up the governor, also replaced all gaskets pertained to the repair, all intake gaskets, all throttle linkage and springs and one head that had a bad oil seal and it now runs ok but..

    New Problem
    Upon starting the mower runs great but the governor will not go back to idle after the throttle is raised. The governor has been adjusted to spec (counter clockwise throttle and governor) and every other way just to try it. The governor arm does not seem to fall back down as it should, if you manually push it down it will idle down and stay that way until it is raised again but it will not do so by itself. We have opened up the motor again to check that the governor is installed correctly and everything is free and installed as to spec. The only thing that was not changed was the governor shaft seal, it weeps a very little but according to some posts we have read here replacing it might not change they minor problem.

    Any help or suggestion would be helpful.
    Thanks in advance.
  2. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,334

    Is the gov arm installed too far back on the gov shaft.
    There needs to be clearance between the arm and the block.
    Sounds like the gov arm is making contact with the block when the engine is running.
  3. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,248

    When you replaced the pan are you sure you got the governor fork turned properly so that it is over the governor cup? Either that or you don't have the governor adjusted properly.
  4. Mark Brown

    Mark Brown LawnSite Member
    Messages: 14

    It is free and to spec (approximately 7 mm (0.3 in)), Thanks.
  5. Mark Brown

    Mark Brown LawnSite Member
    Messages: 14

    Seeing that when the motor was opened that the governor was melted, assume we put it together correctly. We do have a PDF of the tech manual

    We have it so it it rests/rides against 'C' on the image.

  6. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,334

    Are you sure that the "A" washer is on the cam?
    Also check the thrust (in and out ) play on the gov shaft.
    If the shaft is pulled out when adjusted, you may lose your clearance between the block and the gov arm, when the engine is running.
  7. Mark Brown

    Mark Brown LawnSite Member
    Messages: 14

    Funny you should mention that, when we put it together the first time 'A' was installed wrong, it was inside of 'B' snap ring, after correcting this there was no change.

    We will check the play on the governor shaft, Thanks
  8. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,334

    You're slippin Dutch.....

    Multitasking....Beat you by 2 minutes with a customer on the phone and 1 at the counter..Monsoon season is here.
  9. Mark Brown

    Mark Brown LawnSite Member
    Messages: 14

    Update, have replaced the entire internal and external governor, except the shaft and the spring clips and was reinstalled correctly as per the tech manual. The motor does the same thing as before. Motor starts right up on an idle but as soon as you rev it up the motor revs but will not return to idle unless you pull the governor arm down manually, almost like there is a missing return spring somewhere on the linkage or carburetor. The arm is free and does not bind, drag, or rub anywhere internally or externally. We even lightly sanded the end of the camshaft in case there was a bur on it that we could not see or feel. The adjustments were made as per the tech manual.

    We are 100% stumped!

    The motor is located at a shop that is only visited once a week or so and is used on a Great Dane mower that is used to maintain the property. We have had the motor from brand new and has been maintained by for the most part, general maintenance, a few heads and other minor issues but has always been a dream to start and use until now. Really do not want to have to buy a new short block but might end up having to unless this issue is solved.
  10. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Can I play ?!?!?

    With all the carnage you say you found when you opened this thing up, Did you notice a roll pin in the cam gear that's supposed to go into a small hole in cover plate "D" above ?


    Without this pin or the pin not in the cover plate hole, Could cause the governor to react as you describe......

    Oh, Some bad newz..... Kawi doesn't offer shortblock engines, Only repair parts or complete engines.

Share This Page