Prop selection for a 48hp Johnson?????

[hooterville]

i have a 1990 48hp Johnson and am wondering what type of prop i should be running on my setup? It is on a 18' tracker grizzly aluminum boat. The boat is about 800lbs weight before all fishing gear and equipment was added. I do not know what size or pitch i have now. I bought the prop new and it was on a smaller aluminum 16 lowe bass boat.

The prop as some wear ,nicks,and gouges on the blades and i'd like to replace it with another SS. I get about 30mph out of it now and usually run it about 25to 27mph . I do not have a rpm gauge on the boat to know my RPM's.

Ont eh Iboat's store there are pitch sizes from 8to 19. what should i get?

 

[Bondo]

Re: Prop selection for a 48hp Johnson?????

I do not know what size or pitch i have now.
I do not have a rpm gauge on the boat to know my RPM's.

Ayuh,....

Without that Info,... There are No answers....

 

[Silvertip]

Re: Prop selection for a 48hp Johnson?????

Yes -- there is an answer! Just how accurate it is without any WOT RPM data is the problem. The very first thing you could do is to actually look at the prop for the current diameter and pitch and if you are happy with the performance, get the same diameter and pitch. Why on earth would you want to spend a couple hundred bucks on a stainless prop when you have no idea how the engine is performing now? My answer to your question however is that the 40-50 HP JohnnyRudes almost universally ran a 12-1/4x 15 cupped aluminum prop on that size boat. If you run with a light load most of the time you might try and 11-3/4 x 17P. But without any RPM data, go with a 12-1/4 x 15P which is more than likely what you have now.