Re: compression test #'s - good?
A bit of variance there between 3 and 4....in the aircraft bizz (I used to be an a/p mechanic) that would be WAAAAAAY too much, but this isn't an aircraft, it's a boat, and much easier to deal with when the engine "just quits"

Sooo, I'd say unless you are routinely out 20 miles from shore, I'd agree with the above posts and just use it.
Tim