What Propeller for a 1999 Johnson Oceanpro 115

[hikehike1]

Hi Everyone,

I am trying to figure out what would be the best propeller for my boat. My goals in choosing a propeller are getting the best fuel economy and a high cruise speed (speed where the boat has the best fuel consumption) while not putting to much stress on the engine (RPM not too high). My boat is a 1999 Boston Whaler Ventura 180 and the engine is a 1999 Johnson Oceanpro 115, 2 stroke outboard. The model number of the outboard is J115PXEEM. From research I have done using a model number decoder I have found that this engine is the X-Long length of 25". I believe the boat goes 32 or so MPH at WOT (5200 RPM) with two people and 35 gallons of gas. Those are the numbers I remember from last year but they are likely slightly off. The boat has no problem getting on plane relatively quickly. I usually run the boat with about 3 or so people on it weighing around 150 pounds each, 20 pounds of gear, and 45 gallons in the 60 gallon tank. This is an approximately 750 pounds over the dry weight. I sometimes run the boat with 6 or 7 people and close to 50 pounds of gear with a full 60 gallon. The current propellar is the aluminum one that came with the boat when I purchased it used. It is chipped and the only numbers I could find on it without taking it off are 06B&S863 and 04B&S968. Any help in choosing the right propeller is greatly appreciated.

Thanks,
Hikehike1

 

[SkiDad]

your numbers look pretty good to me - think the rpm range for that engine is 5250-5750 and you will get good mileage if you stay close to the middle of that range. So if you are pretty close to 5500 you are doing really good and I wouldn't change anything. By the way there is a guy name Tom Clark in the continuous wave .com forum that deals specifically with all the whalers and can tell you if you are setup correctly.

 

[steelespike]

Welcome,
You have done a great job getting us started.Unfortunately your prop numbers are probably in the only place
you haven't looked,under the prop nut.
I used a prop calculator to do a best guess on your prop size I get a 15" That seems reasonable but it should be turning more rpm.
We need the size off the prop to make a final determination.5200 seems a little low considering the weight you sometimes haul.

 

[SkiDad]

I see Tom found you on THT - cool. He is much more knowledgeable than me - now if you had a Bayliner I could tell you the exact prop - ha ha. You could at least check that you have spark on all 6 cylinders as that boat is lighter than I thought - you won't hear 1 cylinder and that could be costing you top end. If not then at least your know that part is not the issue. A spark tester is about 10 bucks at a local auto store - you just ground it to the block or there are some that are in-line.