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Kawaski 460V Leak Down Test

Discussion in 'Mechanic and Repair' started by ed2hess, Nov 14, 2012.

  1. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,190

    This is an old engine that I was working on to get the exhaust seat ground and the valve lapped. Well I got back to it and thought I had valve fixed since I got good results with leak test on bench. Put it on mower and it wouldn't start. Well put leak tester back on leaking out of the oil dip stick.

    Now what the hell is going on? When the unit was on bench it was not leaking. I put compression tester on and it was in 50 range...but I am more interested in how can you get a good check on those valves if air can get past the rings?
  2. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    The valve could have been leaking so bad before...that there wasn't enough pressure left to show the leaking rings..???
  3. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,190

    Don't they have some type of decompression device on this motor? Any chance that can stay engaged?
  4. Tmurph2960

    Tmurph2960 LawnSite Member
    Posts: 10

    Yes tney do. Adjust the valve lash clearence to .004 to .006. This will insure it is working properly.
  5. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Ed...most have an ACR...I've only seen one that didn't...
    If the ACR was staying engaged..it would leak air thru the exhaust in a leakdown test..
    This engine is taking you to school....
  6. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,190

    I think I am in kindergarten.....the engine has a big logo right on top of the recoil with a big ACR logo :dizzy::dizzy: I got to get the thing back off
    the mower and take that bottom pan off.

    I am ramping up my effort on a 15hp Kohler rebuild in the meantime for use
    on my $75 Scag WB.
  7. pugs

    pugs LawnSite Gold Member
    Posts: 3,022

    ACR would have nothing to do with leakage past the rings.
  8. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,190

    I am getting enough leakage past the rings that it is bubbling the oil up the oil dip stick. My question was how can I tell if I got good seal on my valves? Can't depend on gage if it shows the leak of the rings right? For some reason when I had this engine on the work bench with the piston vertical I performed leak test and everything was fine. Now with it horizontal on the mower with oil it is leaking:hammerhead:
  9. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Ed...how well the valves are seating has become less important now...
    They are probably seating pretty good now...which is why so much air is getting past the rings.
    I know you're looking for some sign of progress to motivate you to tear into the crankcase..
    We ALL get one of these engines from time to time....if it doesn't beat you..it'll make you a better mechanic.
  10. DaveyBlue32

    DaveyBlue32 LawnSite Member
    Posts: 136

    I have a funky one... 460v good compression, runs and cuts great, you have to set the throttle to med-low and it starts on the 2 or3 pull from cold? No choke.... No gas.... Just starts puttering along, I give it a minute to warn up... Then go? What's up with that? Any ideas?
    Posted via Mobile Device

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