[applehead]

I have a craftsman 4.5 pusher here ,won't start and seems awful easy to pull over, so a compression check shows a tad over 60# , I thought this was low ; so I checked it against another mower/ 6.5 simplicity pusher that is known to be good and got the same reading.... so I guess my question is 60 # is really good for these machines ?

I have more experience with chainsaws and sleds than mowers ; usually healthy readings around 150 psi , showing only 60# would indicate the need for a rebuild.
???

 

[rhenning]

Many small engines have a compression release built into them so you can pull start them. It is designed to stop releasing above about 1000 RPM or in normal running conditions. This makes a compression gauge a vertually useless tool on many small engines. Roger

 

[applehead]

rhenning ; I did not know of that , ty for the reply. What is the method for checking the chamber/piston/rings then ? Are the comp. releases mostly accesible (sp) to disable ?

 

[themidniteryder]

Even with the compression release affecting the reading, if I get one in that reads 60 psi and won't start, I won't work on it. Very few are worth trying to save at that reading. A cylinder leakdown test would give you a little better indicator where the problem lies.