Unlimited Compression

[renn90]

My 2007 DF15 registers over 190psi compression in both cylinders, and keeps rising every time I pull the start rope (warm engine, throttle wide open, working quality compression gage). Holds compression for over 3 minutes (didn't monitor longer than that).
Also has compression coming out of the dip stick tube when engine is running, and noticeable air volume coming out of the breather port on the top of the head cover.

What do you guys make of this?

Just changed the head gasket (followed OEM manual to the tee). Changed due to water in oil, and now oil is completely water free.
Starts on first pull when warm
Runs smooth, sounds good, will idle very low

Thanks for any advice you can give

[redlowrey]

Mate you do realize that you have to press the button to release the pressure after each test, if you don't the pressure will stay in the gauge until it eventually bleeds out, and you will get some crank case pressure with the dip stick removed this is because of the pumping action of the pistons being in a small crank case. But in saying that if you had broken rings or ring land there would be a lot more and probably blow oil out of the dip stick.

[renn90]

Mate you do realize that you have to press the button to release the pressure after each test, if you don't the pressure will stay in the gauge until it eventually bleeds out, and you will get some crank case pressure with the dip stick removed this is because of the pumping action of the pistons being in a small crank case. But in saying that if you had broken rings or ring land there would be a lot more and probably blow oil out of the dip stick.

Yeah sure, but even so, the gauge will not show more compression than the cylinder can generate. the main concern is pressure from the dipstick and head cover breather. I thought that would correlate with low compression, but it doesn't seem so.

The main concern is compression coming out of the dip stick tube, and noticeable air volume coming out of the breather port when engine is running.