Re: 3.0 Mercruiser performance options
harveje, I have a 19' bayliner 2002 with the 3L 135hp. It has a 2:1 drive ratio and my oem prop is 14x21. I've tried a stilletto stainless 4-blade 14.25x20 on the boat and maybe loose 1 mph at top end, not really noticeable, but the holeshot is completely different. The prop has so much more bite that you can hear the engine really work in the mid range when the boat climbs out of the hole. It's sort of the opposite of what you want, because you're lacking low end torque with the 4 cylinder. You're better off having a 3-blade that'll slip more and allow the motor to rev higher. Not that I'm trying to talk you out of trying props, just don't go spending a couple hundred and get stuck with a prop you won't like. If you're running a 3-blade 19" prop and you're holeshot is so-so I can guarantee you a 4-blade 20" prop will be worse but you may be happier with mid-range performance.<br /><br />for the original topic, there's pitch-shifting props which have lower pitch at lower rpms for holeshotting and the pitch changes higher as rpms climb for top end speed. They're not cheap but may be a good solution to your problem.<br />As for motor mods short of a v-6 or v-8, don't know what year you have but maybe upgrade to the newer style heads, find a custom set of heads, weber carb, look at thinner head gaskets if they're available, change over the valvetrain to roller fulcrums, modify your valve lift or have a custom cam made, pull the whole motor and do new pistons with new cam. And reducing weight in the boat is always a good idea.