Reports on the net suggets that a leak down test is the way to go
some reports that 45 psi will start an engine but be a bit powerless
70 + is pretty good and excellent is around 90-110 psi
I have never compression tested since I got caught ( inexperience) with a motor that felt it had no compression only to find ( after a rebuild) that it still had the same amount of compression
after making inquires of the local small engine shop I was informed that there is a special grind of the cam shaft that produces a situation when the valve is held open to reduce compression to allow it to start on a pull cord and the first time it fires the engine speed picks up and the valve is not affected by the grind and so it starts
engines as low as 4 hp have this system ( B&S 5hp lawn mower
victor 2 stroke with a compression control unit in the head and larger motors up to 20 hp with pull cord start)
so basically it is this
if you feel that the resistance as you pull the cord is not as it should be contact the service section for the engine make and see if it has a decompression start assist and if not then you can look for other faults
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