Hour meter

[Ken Juul]

I like that logic!  But I've spent too many boat bucks this year to needlessly wreck a working tach and have too many guest drivers to not have one.

[Ken Juul]

Some additional info.  I tried to slice the hour meter into the fuel pump circuit as the installation instructions showed.  With the meter in series the meter would work, but the pump would not.  I guess I could have put it in with a parallel connection, but instead found an ignition "on" hot lead on the terminal block for the instrument panel and took the power from there.

[Indian Falls]

Ken your hour meter is not meant to and probably cannot pass the current needed to drive the fuel pump motor.  That's why it wont work in series.  Hour meters need only 12 volts and you can connect to the plus wire of your pump but the hour meter ground should go to ground alone not to the input of another device.
The minus connection on your pump is ground, so if you put the hour meter "across" the fuel pump connections you will have a fuel pump hours meter as the meter will only run if there is power to the pump.

[Ralph Masters]

And you only run the fuel pump if you run the engine so it'll be an engine hour meter.  Just be sure to make note in your maintenance log of the hours that were on the old hour meter so the next owner, if there ever is one, knows the hours total on the engine.

Ralph
Ciao Bella