1965 johnson 40hp what are my options (heavy boat)

[mcurcio1989]

I have built a 24 foot quadtoon tiki boat (two 25 foot toons on the outside and 2 20 foot toons on the inside, see picture). I picked up 1965 40hp Johnson for it. I am not trying to go fast just trying to push it along. This boat does not like to move along through that water I can just tell that from pushing it around at the dock. It is getting it up to maybe 10-12 mph which is okay by me but Im thinking that for the health of this motor it would really help to have the lowest pitch possible. I looked at the serial numbers on the prop and they are indicating a 11.5 inch pitch which seems to be the lowest they make for this motor. Questions

-Should I try and find a lower pitch?
-Pending the previous question there is a shop in town that re-pitches but can this prop handle that? (I dunno)
-Are they any aftermarket options I am missing.

Thanks

haha sorry its just all guys in this pic for the trial run - I know somebody will say something

 

[Texasmark]

Re: 1965 johnson 40hp what are my options (heavy boat)

I'd stay with your 11.5. Hard to say it won't work and seems to go lower would be a lot of trouble. Would bet there is absolutely no data to support a technically supported answer due to the uniqueness of your boat.

Mark

 

[steelespike]

Re: 1965 johnson 40hp what are my options (heavy boat)

What a great idea! Temporarily a prop shop may be able to remove some pitch.
Keep an eye on ebay a prop is sure to pop up.
The motor at wot needs to be within its' rpm band 4000 - 5000.
Once its propped right you can run it at whatever rpm you like.Best practical mileage should occur about 6 to 8 mph.
Most pontoons do real well at displacement speeds.
If it is badly over propped you really shouldn't run it beyond displacement speeds 'about 6 mph' for an extended period.
If you check ebay right now there rate props listed for 1965 40 hp johnson.
One listing lists about a dozen motors that the prop fits from 51 so there mane any number of those application that might turn up in a pontoon size. Un fortunately the stock 51-55 25 hp prop is essentially the same size as the 40. But again a pontoon size may pop up listed for a 25.