1997 Larson 226 5.7gl sx cobra

[northern sparky]

hi everyone, just picked up the new boat. It's a 97 Larson 22-1/2 foot bowrider with a Volvo 5.7 gl carb motor and a 1.66 sx-c1 drive. I figure it weighs around 4000 pounds with gear and people. Runs great, starts right up every time, idles nice all day, throttles up nice. Had the drive off, checked and greased gimbal and u joints. No indication marks on the prop, it's aluminum. Wide open throttle gets me up to 44@about 4500 rpm on the gps and cruises at about 30@3300 rpm. I don't want to run all day at top speed but I figure I can get a little mor out of her... Any recommendations on what to try first with the prop? Any one able to point me in the right direction of some accurate motor specs? I figured the wot rpm should be closer to 5k. Any one with the same setup? Thanks in advance

 

[steelespike]

As usual I am Volvo challenged. Did you look under the prop nut for numbers. My Volvo info lists a 1.60 ratio, and rpm 4200-4600.
Using your 1.66 ratio 4500 @ 44 mph Guessing 12% slip I get approximately a 19" prop.on there now.
Based on the chart I have your just about there at 4500 @ 44 mph. Obviously guessing the slip could throw off the present prop calculation.