[Capt Len]

Not much experience on that engine but know that is retarded. One standard shim equals one degree. Putting in shims will advance it. Makes the pump piston meet the cam follower sooner.

 

[Capt Len]

Reminds me of back in the day when we advanced the cam a tooth looking for performance. (Flathead Fords) The dots can be tricky (not straight cut gears )and the cam rotates as the gears slide/mesh. Seems to me that it is similar but I've only done a couple of yanmars so no expert. There used to be a guy at Wilson and Proctor Damm good, check it out.