another pitch question - i have a 12p

[westy66]

i have a old 16' fiberglass runabout (closed bow) with a 70hp Mercury OB on it. i havnt even had the boat on the water yet, but i want to get a new prop as the one on there is beat up bad. it has a 12 pitch 3 blade prop on it now. i am probably going to just be cruising and towing a tube with her. wont the 12p prop make me rev REALLY high? i was going to just buy another, $90 aint that bad. should i go higher? 13p? 15P? i dont have a tach on the boat anyway

thanks in advance...
Bob

 

[steelespike]

Re: another pitch question - i have a 12p

Need more info.What year is the motor? You should get a tach.Tinytach it is reasonable easy to install and will work on any motor.
Without the rpm there is no way to know which prop and no way to tell if the motor is operating within it rated rpm range.
If the motor 83 or older a 12" is probably pretty close.

 

[westy66]

Re: another pitch question - i have a 12p

its a 1978 Merc 700 70hp. thanks. ill start with the 12 and see what happens.

 

[steelespike]

Re: another pitch question - i have a 12p

There ya go.Get us a lightly loaded wot rpm and speed by gps.