Yanmar 2GM20F - Decompression lever OFF position

[Newadventure]

Hello,
I am about to check my valve clearances, and following the procedure in the workshop manual to remove the valve cover, the first step is to move the decompression lever to the OFF position. Does this mean decompression is off (so i am in normal operating position) or that compression is off (ie exhaust valves forced open)?
Thanks

[sailorchic34]

No need to mess with the decompression levers. Just remove the two cover nuts and tap lightly on the cover to remove it.

[Newadventure]

Understood. Thanks very much

[RaymondR]

They probably intend that instruction so that the nuts become finger tight and can be spun off readily by hand. When you de-compress you lift the valves off their seats against the closing pressure of the valve springs which lifts the tappet cover up against the hold down nuts.

[Wotname]

Originally Posted by Newadventure

Hello,
I am about to check my valve clearances, and following the procedure in the workshop manual to remove the valve cover, the first step is to move the decompression lever to the OFF position. Does this mean decompression is off (so i am in normal operating position) or that compression is off (ie exhaust valves forced open)?
Thanks

AFAIK, it means the levers should be in the normal engine running position i.e. the cylinders not decompressed; for the reasons suggested by RaymondR.
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But if they meant the other way, then that would help pop the valve cover off when the nuts where undone.

I reckon it doesn't matter when moving the valve cover but I would always have the levers in the "normal running position" when refitting it.

[GordMay]

Greetings and welcome aboard the CF, Newadventure.