 Need Prop Help - 1994 21' SeaRay Laguna
I recently bought a 1994 21' SeaRay Laguna center console and swapped out the original 150 hp Merc for a 2005 Yamaha 200 OX66. The Yamaha came off of my old 1981 24' HydraSports cuddy. I fully expected my speed/fuel burn numbers to be better on the 21' Laguna than the 24' HydraSports (smaller boat, no cuddy/curtains, etc), but the performance and economy are actually worse. Right now, my cruise at 4000 rpm is 21-22 kts; on the Hydrasports, it was 23-24 kts. Top end at 5600 rpm is 33-35 kts, which is about the same as the HydraSports. The Laguna seems a little bit more sluggish to plane than the old HydraSports, and my fuel economy has gone way downhill. The engine appears to be mounted correctly. My guess is that I'm not propped correctly. I'm currently running a prop that I've had for a long time (same prop that I ran on the Hydrasports), but I'm not sure what the pitch is, nor do I see any markings on the prop.How do I figure out what size prop I'm running now, and any suggestions for getting a little bit more out of this boat/engine combo? Thanks | 
