RE: Some Basic Prop Questions
Now we're getting somewhere. An OS 91 FS should easily pull 7 1/2 lb straight up --- you were seriously underpropped with the 13-7 & I'm sure that the 14-8 will show a noticeable improvement. At 580', your elevation is not affecting your engine output to any significant degree, so the engine should develop pretty close to its max HP -- it will probably pull OK with the 14-8 -- on a cool day it might even pull a bit more prop than that. With the 14-8 you can expect a little more level speed than you get since you re-tuned the engine, & a big chunk more vertical.