boater435 wrote:
I belive my tach is not reading properly. I have an albin 27 family
cruiser with a lehman diesel the rpms seem to exceed the redline by
alot 500 to 800 rpm (guessing) the tach stops at 4100. I don't think
the engine would go this high. I am trying to find something to check
the rpms so I can calibrate the tach or repitch the prop. Any help
would be appreciated. Paul, Cape Cod, MA

There is a little gadget that has a rubber tip and records revolutions
sort of like a micrometer or caliper. A friend had one and helped
me calibrate a tach that was not reading properly after a pulley had
been changed. You hold it against the crank pulley for a minute and
it tells you the revs.

Somewhere I have another that I found at a flea market, but can't find
it now. I seem to remember the word "Starette" stamped on it - they
made a lot of small instruments.