Prop size for 4-107
Anybody have any idea what prop size would be correct for a Perkins 4-107 in a 41' Gulfstar. From what I can tell the 4-107 should have an rpm of 3000, but I can only get 1800. I have a 16x16 prop and I am wondering if it is wrong. Been running this way for years and seems ok, I can only get about 5 knots out of it. I always thought that was all I would get. But, I started to wonder ifI the prop my be an issue and I wanted to see if anyone might know.