Did a compression check on my kt19...

[jimmystractor 171]

I had almost 80 in one cylinder and 70 in the other. I read that under 100 is not good. I am currently running 10w-30 Synthetic. Anything I can do to preserve this motor to keep her running okay?

[Chris727 2,015]

I'm surprised its running as well as it does. It may need a valve job or it could possibly have worn rings and or piston/cylinder bore wear.

[jimmystractor 171]

Well, I am not too concerned anymore. I decided to do a compression check on my 2003 Kohler Magnum 18. It runs great, uses no oil and doesn't smoke. It was 80 in both cylinders. 

 

This is a new compression tester but it is a $30 one from Farm and Fleet.

 

Do these motors just have a lower compression? 

[fishnwiz 3,290]

I have had engines with what is considered low compression run like a top. I have also had engines with 100 plus compression run like crap. 

Low compression seems to effect ease of starting in some cases and not much with others.

Not really sure what all that means...just stating my observations from my past experience .

Edited November 13, 2016 by fishnwiz

[MikeES 458]

Was that a cold test or when the engine was warmed up?

[Kenh 37]

Many engines have a compression release so "low" compression is normal.  A better tool to use is a cylinder leakdown tester.  This is not dependent of engine rotation and can tell you if the valves are leaking or you have bad rings.  Compressed air is used to supply the cylinders "compression".  You can listen at the exhaust, intake or oil fill for leakage.  The tester also gives you a percent of leakage.

http://www.dsmtuners.com/threads/compression-and-leak-down-testing.338152/

Ken

[Simplicity725 15]

If it runs fine, then I wouldn't worry about it. But if not, then a simple rebuild should do the trick. Food for thought.

[MikeES 458]

The Kohler flat twins do not have a compression release so you can take a compression test.  To get an accurate test, first warm up the engine, then remove both plugs, open the throttle wide open (you will get a very low reading if you do not have the throttle all the way open), run the starter and spin the engine until you do not see the needle climb anymore usually 6 compression cycles or less.

Most of my twins have a compression above 90 psi, the couple that I have that I would call in very good condition have a compression around 110.