Johnson 18hp needs a new prop??

[hondarider188]

My 1960 Johnson 18hp cant get up on a plane but it sits just right on the edge of planing out and jsut plowing on through. but do i need a new prop and if so what would be the best on to use to get up on to plane in a pretty decent time and still have a good speed its pushing a 14ft aluminum feathercraft with and average of 2 people with just normal fishing gear(2 tackle boxes and poles) then a full six gallon gas tank with a small tool box in the back with motor then a small 25lb thrust sears trolling motor in front with a battery. And the prop on it now is a 9x10 wich was stock for the time and has never been changed to my understanding and it has seen a few rought times with some small dings and small bends.

 

[SparkieBoat]

Re: Johnson 18hp needs a new prop??

you could try a new 9 pitch, it would be nice if you had a friend who could loan you a 9 pitch prop to test with first, but unfortunately it is kind of a guessing game. the motor has to be in good running condition first. also I have had 15 HP motors on 14' alum boats and found it to be underpowered in my opinion, but it would get up on a plane. a 25 seems to be more up to the job. a dinged up prop can hurt also.

 

[Texasmark]

Re: Johnson 18hp needs a new prop??

My 1960 Johnson 18hp cant get up on a plane but it sits just right on the edge of planing out and jsut plowing on through. but do i need a new prop and if so what would be the best on to use to get up on to plane in a pretty decent time and still have a good speed its pushing a 14ft aluminum feathercraft with and average of 2 people with just normal fishing gear(2 tackle boxes and poles) then a full six gallon gas tank with a small tool box in the back with motor then a small 25lb thrust sears trolling motor in front with a battery. And the prop on it now is a 9x10 wich was stock for the time and has never been changed to my understanding and it has seen a few rought times with some small dings and small bends.

I used to water ski behind a 14' wooden boat (much heavier than your alum) and a '59 Evinude 18 using the stock 9x10 prop and obviously you have to be on plane to be able to ski......now I grant you I was on 2 skis and I was a late teen, probably 170-180# and didn't set any speed records, but we did it many time. You may have more problems than just your prop. 1960 is a long time ago and if not changed, time for some updating.

HTH,

Mark