james__12345
Petty Officer 2nd Class
- Joined
- Jun 26, 2012
- Messages
- 196
I have a 1976 Johnson 6hp as a kicker on my 1648 lowe flat bottom. The current prop is a two blade 8x7 1/4. I currently am only getting 4200 rpm at wot. The prop isn't in great shape so I feel like just replacing with a new one just like it may get me closer to the 4500 which is the lower end of the range. I see here on iboats that there is a 7 pitch available, but it is a 8 1/4 diameter three blade. I get the basics of changes in prop on rpm, but between these two changing diameter, pitch, and blade count I'm at a complete loss for what the better choice would be. I'm currently getting around 6 mph from the kicker best I can remember if that makes any difference.
Also, the 4200 rpm was with 2 people which will be my usual load. But with some additions I'll be making soon (front and rear decks and a generator) the typical load will more like 4 people weight wise. How much difference does a couple hundred pounds generally make on rpm for a flat bottom with a motor that won't get on ever get on plane. Will it change things enough that I should wait on picking the new prop?
Also, the 4200 rpm was with 2 people which will be my usual load. But with some additions I'll be making soon (front and rear decks and a generator) the typical load will more like 4 people weight wise. How much difference does a couple hundred pounds generally make on rpm for a flat bottom with a motor that won't get on ever get on plane. Will it change things enough that I should wait on picking the new prop?