Larson 17' Volero w/Evinrude 48spl - prop?

[philobite]

My '68 Larson 17' Volero 177 is fitted with an '87 'Rude 48spl. (I know, it's underpowered). The current prop is a 12 1/4 x 15 aluminum.

Best speed I've gotten out of it (gps) is around 22mph. I'm wondering if I can boost my top speed a bit by switching to a 12 1/2 x 13. Any thoughts or recommendations? (And no, I don't have a tach).

 

[Silvertip]

Re: Larson 17' Volero w/Evinrude 48spl - prop?

Probably won't increase speed but it will give you better hole shot and keep from lugging the engine. PM me -- I may be able to help you.

 

[billythegreek]

Re: Larson 17' Volero w/Evinrude 48spl - prop?

My '68 Larson 17' Volero 177 is fitted with an '87 'Rude 48spl. (I know, it's underpowered). The current prop is a 12 1/4 x 15 aluminum.

Best speed I've gotten out of it (gps) is around 22mph. I'm wondering if I can boost my top speed a bit by switching to a 12 1/2 x 13. Any thoughts or recommendations? (And no, I don't have a tach).

I had the same exact boat many many years ago with my father. We had an 80 hp Evinrude and the boat topped out at 34mph. Had more fun on that boat than on any other one I've owned since.

 

[steelespike]

Re: Larson 17' Volero w/Evinrude 48spl - prop?

In my opinion working without a tach is pretty much a waste of time.Without a tach its really impossible to evaluate your setup.
There could be motor problems,setup problems,boat/hull problems.
Working backwards(not a good idea) on the prop calculator Guessing 10% slip your motor is turning about 4100 rpm @ 22 mph.
That would indicate you need a 5" reduction in pitch,not practical.That would put you close to what a 20' pontoon would require.
If my guesses are right something outside the prop is causing problems.There is no doubt in my mind with a proper setup you should make about 30 mph or more with a light load and proper setup.
A induction tach will work on any motor for $50 or less.