Which Prop 10 3/8 X 14 or 10 1/2 X 12

[diveman05]

Happy Sunday everyone! Just like the title i have a 1970 Johnson 33hp engine, it came with 2 props, looking for more top end speed than anything should i use the 10 3/8 X 14 or 10 1/2 X 12, my prop knowledge is at best extremely limited to be honest so any advice here is greatly appreciated.

Have a great one!

 

[BonairII]

Re: Which Prop 10 3/8 X 14 or 10 1/2 X 12

You need to install a tach to correctly prop your motor. Propping "by ear" is impossible.

Get yourself a portable(or permanent) tach and post your rpms at WOT. The transom bracket on your motor should specify optimum rpm range for your motor.

 

[steelespike]

Re: Which Prop 10 3/8 X 14 or 10 1/2 X 12

We're going to get you going but if you read the stickys at the top of the prop forum.
and the helps at the prop store page it will help you understand a little better.
Prop size would depend on the size and weight of the boat and the typical load and activities.
In 1970 it came with a 10 1/2 X 12 but the final size would depend on the the boat etc.