Forum Discussion

palmerjp's avatar
palmerjp
Explorer
Jun 22, 2016

Compression for kohler magnum

I need the allowable for a kohler magnum modles m18 and m20

Thanks
Joe
  • Sorry. That would be page 4.4 in the troubleshooting section.
  • Tom_M wrote:
    On page 31 of the service manual:

    To test compression:
    1. Remove the spark plugs. Install compression tester In each spark plug hole.

    2. Set the throttle and choke controls to the wide open position. Make sure air cleaner and exhaust system are not restricted.

    3. Crank the engine using the starter motor. Take several readings for both cylinders.

    If the difference in pressure between cylinders is 15 percent or greater, or pressure is less than 90 psi, check for the conditions below:


    Sorry. The service manual I have doesn't have page numbers like that. Just section and page number of that section ie 2.4, 6.2, 8.11
  • On page 31 of the service manual:

    To test compression:
    1. Remove the spark plugs. Install compression tester In each spark plug hole.

    2. Set the throttle and choke controls to the wide open position. Make sure air cleaner and exhaust system are not restricted.

    3. Crank the engine using the starter motor. Take several readings for both cylinders.

    If the difference in pressure between cylinders is 15 percent or greater, or pressure is less than 90 psi, check for the conditions below:
  • Thank you both. I didn't see it in the service manual. I do have about 83 lbs on both cylinders. whoo hoo.
    I can now move on
  • It should start at 75 psi, less than 70 indicates issues. The cranking compression is low because it is equipped with an automatic compression release, a leak down test gives a much better indication of engine condition. A well equipped small engine shop should be able to do this for you.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,210 PostsLatest Activity: Mar 02, 2025