change props? 2 motors

[coolguy147]

well first off i have a 1959 evinrude 10hp. i finally got a tiny tach commercial and it works great. im on a pontoon boat. 20ft 8ft wide. 1964 riveria cruiser. with almost full tank. small bucket of tools fire extinguisher etc and some rope. plus 2 people including me. im about 135 while my friend about 110-120 pounds. on board. the motor only revved to 4200rpm average. it makes 10hp at 4500rpm but the recommeneded range is 4000-5000rpm. should i move down a pitch or two?

second motor is a 1958 35hp johnson. its on a 1962 orlando clipper. the boat is 15foot long alumium. runabout style with windshield front and back row seating. the boat planes very fast. the motor revs to about 4900-5000rpm. it makes 35hp at 4500rpm but the recommended is 4000-5000 rpm. should i move up a pitch?

 

[steelespike]

Re: change props? 2 motors

Without speed especially on the 35 its difficult to tell about a prop change.
Really need the present prop size max rpm and speed on both setups.
It would appear the 10 Could use less pitch and if you could find a 4 blade prop (not likely)would probably do better.But again without prop size etc. difficult to tell what is needed.

 

[coolguy147]

Re: change props? 2 motors

oh im sorry i completely forgot to name the pitch and dia of the props. my bad

the 35hp has a 10dia. by 12 pitch prop

i dont know what the 10hp has

 

[steelespike]

Re: change props? 2 motors

The 58 big twin came with a 10 3/8" X 13 3/4 prop. Based on your description
and rpm you probably could go up one size in pitch.The 10 came with a 8 1/4 X 8 1/2
of course the final prop size on both would depend on the final application.

 

[coolguy147]

Re: change props? 2 motors

welll i got a different motor the 1961 merc500 which im going to be putting it on the boat that has the 1958 35hp motor. i most likely will leave it on there.

i think i will leave the props on the motors. since they work good and i dont feel like paying for a new one. plus the new one or used might have to get rehubed 40$ down the drain.

my plan is maybe the 35hp on the pontoon(that thing already guzzles gas cant imagine it on the pontoon) 10hp future 13 1/2 foot john boat. need to get title from the guys and plus its been in our yard for 10 plus year then 50merc for the ski boat 15foot