1962 40 hp johnson electromatic prop pitch?

[gary cooper jr]

62 Johnson 40 hp electromatic, I will be running this motor on a16 ft 72 in beam aluminum jon boat, what prop pitch will work best?

 

[RCO]

What prop is on it now, and what kind of performance are you getting/expecting?

 

[jimmbo]

Your engine has an rpm range of 4000 - 5000 rpm. Any idea what rpms you are currently running, and with what prop? If not, I would recommend an 11 or 12 in as a starting point. And if you don't have a tachometer, get one

 

[F_R]

In the absence of a tachometer, probably a 10 1/2 x 12. Maybe a 10 1/2 x 13 if loads are light. As I remember it, they came with a 14" which was pretty useless.

 

[jimmbo]

Some years they came with a 13 1/4, others 13, still others 12, and 14. Gear ratios never changed...

Early 60s 14"
Mid 60s 13 1/4"
Late 60s early 70s 12"
Mid 70s 13"

On our 14 ft Skagit with a 1963 40hp Electramatic we usually ran a 12in. I tried a 13 1/4 I found in a shed, it would barely plane the boat, but the motor was in bad need of a tune up. Next season, after a tune up, I tried it again and it did go a bit faster than the 12, but it was slower on hole shot.