perry 82 #1 Posted August 12, 2009 got a 8hp kohler K181 on a wheel horse commando 8 tractor. it only has 40psi compression. do these older 8hp engines have the enternal compression release on them ?. i know the 10hp & up do but cant remember if the 8hp's do. just checkin before i tear into the engine. it seems to run good but is lacking power. thanks.....perry Share this post Link to post Share on other sites
big mike 13 #2 Posted August 12, 2009 Depending on its age it could have an ignition retard cam or an ACR cam. I'm not sure how you would know other than to pull the head and see it the exhaust valve is lifted off its seat(ACR). Share this post Link to post Share on other sites
VinsRJ 721 #3 Posted August 12, 2009 Compression tests on K-series Kohlers 7hp and up is complicated by a couple of factors. 1) Like stated above the ACR is a factor if so equipted. 2) If your unit is electric start the ACR was/should have been disabled but, that is not always the case. So again it maybe a factor. 3) and then there is the ignition retard equipted units The only way to see for sure is to pull the oil pan and look at the cam gear. Are the ACR springs still connected to the fly weights? If so, then the exhaust valve is letting compression by, if not, then the exhaust vavle is not being actuated by the ACR and is shut all the time. Is the points lobe of the cam actuated by the wieghts directly? Then its ignition retarded. You could pull the head and do a visual on the valve but that again is not full proof. To get around all of this tear down work you will have to rig some way of spinning the motor in reverse or in a clockwise rotation (from the PTO end of the crank) thus eliminating the ACR factor to read the compression. If I may ask, what triggered you to do a compression test in the first place? Share this post Link to post Share on other sites
piecrazy4 0 #4 Posted August 21, 2009 another way to find out is to check when the breaker points open Share this post Link to post Share on other sites