The 4mix has decompression on the cam gear.If I spin it with a 1/4 impact will it be fast enough to check compression?
The trimmer bogs down when it hits heavy grass. I changed carbs, adjusted valves, changed cam gear,I think it may be carbon buildup on the valves or it is just worn out. It is 18 years old. It starts fine and runs fine but if you hit the string in the ground it will bog the engine down.Sometimes it will cut off when you let go of the throttle.
Update! I got the 10mm adapter for my compression tester. Spinning the engine with a drill to offset the decompression lever I got 90psi.I don't know if this is low for a 4mix.
#3
StarTech
– Install compression gauge.
– Move slide control to "STOP-0".
– Set choke shutter to open.
– Pull starter rope vigorously and
quickly several times.
– Note compression pressure.
If the compression pressure is
below 6 bar, check valve clearance
and readjust if necessary, b7.2.
If this produces no improvement,
check the cylinder, valve seat,
piston and piston rings for scores or
other damage.
The design specification is 6...7 bar.
