Prop for Mariner (Tohatsu) 30
On succesfully upgrading my Marathon 25 to 30 by changing carb gasket and timing, i fitted a tiny tach to see what RPM i was getting.
On a 4m inflatable with a 9.99 x 13 prop the max i could get at WOT was 4700 rpm, so below the recommended 5150-5850. I couldn't identify top speed as i didn't have GPS, but will have one next trip out.
From reading other posts on the subject, i need to increase the pitch size?
So bearing in mind i dont want a stainless steel prop(due to where i use the boat), what size would you fit as a starting point and can i expect any speed increase over the current prop and is it worth doing?
Many thanks in advance.