70 johnson prop

[merlin01]

hello,
i`m trying to find out waht is the best prop for my 1981 johnson 70hp engine,
my boat weighs about 2000lbs when kitteed up with 3 on board,i`ve got a 13 3/4 x 15 ali prop at the moment but lose power on full revs,not sure of the revs doing as cant figure out how to wire up the rev gauge and cant get wiring harness for the control box(well not in the uk anyway)i`m getting 20 -- 21 knots
at the present,the previous owner had a 50 tohatsu on it and was getting 25 with 3 on board,
thanks and any help or advise very grateful
mike

 

[jay_merrill]

Re: 70 johnson prop

Try to get that tach going because its pretty hard to be able to offer advice without knowing what rpm the engine is running at.

 

[steelespike]

Re: 70 johnson prop

You could get your self a tiny tach,very easy to hook up and may be able to use on a number of motors.pretty reasonable price.