Compression on a Kohler equipped Z HP

Discussion in 'eXmark' started by brucec32, Dec 30, 2002.

  1. brucec32

    brucec32 LawnSite Platinum Member
    Messages: 4,403

    Hi, thanks for having this forum for answering our questions. I want to check the compression on my 4 1/2 year old lazer Z HP with the 18 hp Kohler engine, just to see how it's doing. I couldn't seem to find what the compression specs are in my manual anywhere. Can Exmark provide these figures for me?
  2. eXmark

    eXmark Manufacturer / Sponsor
    Messages: 4,258


    I know that most of the engine manufactures have some type of compression release. Most of the compression test are not accurate they vary between 120 and 160 psi.

    The manual says to do a leak down test. I will try posting the page in the manual that talks about the troubleshooting.

    I will try to get you some better info on this procedure. I will post again.

    Thanks, Fred.
  3. Jman

    Jman LawnSite Member
    Messages: 217

    Most Kohler twin cylinder engines do not have a compression release camshaft, especially if they are equipped with a solenoid shift starter (looks like a small block chevy starter). If it has the solenoid shift style starter the compression readings are normally 150-180 lbs. There are a few manufacturers that request solenoid shift starters and compression release camshafts so their units will start in the cold weather. With compression release cams you can see readings of 85-120 lbs compression.
  4. brucec32

    brucec32 LawnSite Platinum Member
    Messages: 4,403

    Thanks for the replies. I checked the compression yesterday and one cylinder consistently read 148 psi, but the other was only showing about 85, which concerns me. I will go check to see if I have the solenoid shift starter. I switched to mulching this year and need lots of power and thought it might be losing a little late in the season. I have about 1,000 hours on the mower.

    Curious, does anyone know what range of costs I'd be looking at in repair costs if I took it in for the repair and it needed to be broken down to fix? Past a certain point, I'd rather use it till it becomes too weak, then invest in a new engine rather than several hundred in repair costs.

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