Johnson 9.9 Outboard Prop Pitch?

[Svdestiny]

I am trying to replace the prop for my 2005 Johnson 9.9 2 stroke outboard that I use on an older 9ft, soft bottom Avon inflatable. I find what I need online but I have to choose a pitch I have no idea, the current prop is original and I don't recall anyone discussing pitch when we bought it, no markings to be found, and although we have a cheapie tachometer I don't think we would get helpful info from this chipped, cruddy old prop. So, I know it's a 9 1/2" 3 blade, but should the pitch be 7" 8" 9" 10"?

I don't need performance/speed (ha ha). Just average speed/oomph for tooling around. Any ideas? I was thinking of using 8" pitch but that is just a guess.

[motion30]

By the 7pitch
it will get you more acceleration

[Svdestiny]

Thank you thank you thank you. It's been driving me crazy!

[lancelot9898]

I had a 5 hp Nissan 2 stroke and I was not happy with the original prop which came with it, so I exchanged to for another prop. I wanted to be able to plane that inflatable with me at 200lbs and my wife at 120 and it was not possible with that original prop. I don't remember the pitch involved on either, but I'm pretty sure that I went with the highest pitch. And while it did not accelerate as fast as the lower pitch, it did obtain a higher speed thus allowing us to plane with that much weight.

[Svdestiny]

I don't need to plane (would probably toss the dogs off ). I just need a pitch that makes the poor old Johnson happy.

[djmarchand]

Buy the smallest (flattest) pitch as others have said. I assume that you are driving an inflatable. These don't need a course pitch as they won't go that fast anyway. They nead a flat pitch prop for thrust while accelerating.

I downsized the prop on my Nissan 9.9 hp 2 cycle. Before I could only plane with two on board. With the flatter pitch prop I can plane with 3 and a 40 lb dog and groceries.

David

[Svdestiny]

Huh. I actually found a local (marathon fl) inflatable parts guy who seems to know! He says that the orig outboard came with a 9" pitch. Now I just have to decide if I want to go smaller, ir bigger based on some good advice here. I'm leaning to smaller....

Thanks to EVERYONE

[a64pilot]

if you don't want to go fast, go with the flatter prop, with a flat prop it will pull like a tug boat, but you will give up speed most likely. should be easier on the old motor as long as you don't over rev it.