Re: bouncing tach
A "bouncing tach" on a Perkins 4-108 is often caused by the alternator cycling on-off when one's batteries are fully charged. Try leaving your charger off for a day or so with a small load applied to to your batteries--lights, a refrigerator or whatever-- and then see if you still experience the same issue. We found this to be the case on our boat and now overcome it by simply applying some loads to the batteries when it happens.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."