Prop Size for Yellowstone Lake

[kennharriet]

We are headed to Yellowstone again this summer and I need to purchase the appropriate prop for my Honda BF90. Yellowstone is 7,700 ft. My current sea level prop is 13.5x15. I’ve read that prop size should be reduced 2” for every 3,500 ft above sea level. What would be an appropriate prop and what RPM should I be trying to achieve, knowing that density altitude already my HP reduced almost 25%. Thanks Ken

[Wood Zeppelin]

I just went through this going from sea level to Lake Powell, around 3800'. A local shop gave me a recommendation. It wasn't just the pitch that changed, also the diameter. I can't remember the specs right now, but I recommend calling an outboard repair shop somewhere near the Yellowstone area. They probably deal with this a lot.