I could use some help with prop

[gdshepard]

I purchased a 26 foot 92 Lowes pontoon with a 93 50HP Evinrude. I ran this for one season but was unhappy with the speed about 7 mph. Last summer I lost the lower piston. I found a used 83 115HP Evinrude and put it on the boat. My speed is now around 15 or a little better but my RPM's at WOT is about 4350. I was thinking of changing the prop to put the WOT at about 5300-5500. With price in mind what would be the better prop, blade number and or type. I have a 13x19 3 blade aluminum, I think it is a Evinrude prop.
Thanks for any help

 

[Silvertip]

Re: I could use some help with prop

A 19P prop on a pontoon is way too much pitch as you have found out. You need to drop pitch by about 4 inches which will gain about 800 RPM and perhaps a little speed. Keep in mind that just because you raise the RPM with a pitch change that this does not mean you have a corresponding speed increase. It simply means the engine is now running in its recommended RPM band. You may actually pick up a little speed because 4 inches of pitch translates to 800 RPM (roughly) which puts WOT at 5100. Once the engine is in the power band it may rev to 5500 which would gain a little speed. A 26 foot pontoon is not going to be a speedy vessel. You should also make sure the tubes don't have any water in them and that the engine is actually making full power (as in have it tuned up).

 

[mthieme]

Re: I could use some help with prop

4" is conservative and still a little pitchy.
Most toons I see are smaller though - 20' with less motor.
They are pitched 13 and below.

 

[gdshepard]

Re: I could use some help with prop

Thanks for your help. The logs are dry and the motor runs great, but maybe I'll run some seafoam to decarbonize it in the spring. The motor came off a bass boat. Once I got it on the pontoon and in the water I knew I needed to go to a 15 - 13 pitch. But is one prop better than another...staying in the $100 -$160 range.

 

[mthieme]

Re: I could use some help with prop

OEM is good, Michigan is good, I haven't really found one better than another.
You might try eBay...could probably scare up one for under $100.

 

[Silvertip]

Re: I could use some help with prop

There are some pontoon specific props, some of which are four blades with "elephant ear" blades. These props provide excellent push and work better than conventional props in reverse.

 

[gdshepard]

Re: I could use some help with prop

where can I find an elephant ear prop at ?