V20 with Black Max 150???

[randymbtech]

Thanks for the advice guys. The cavitation plate is level with the very bottom of the transom, it looks right to me. I have to check and make sure the tach is set up right, the boat used to have an Evinrude, not it's a Merc, maybe the tach is wrong? I do think the prop is a bit too small, just because of the way the boat comes out of the water like a rocket. I need to try and find a Mirage Plus 19 to try out.

[bigshrimpin]

Randy - I know your tach is porked. You wouldn't be able to turn over 5800rpm with that motor unless you removed the spark advance module/idle stabilizer (or it's broken) . Assuming you have average prop slip (about 10%) . . . your RPM's right now are really about 5100/5200 with a 2:1 ratio lower unit to reach 36mph. (that's just simple math)

Don't bother with the 19 mirage plus. There is no way that 2.0L motor will turn the 19P and push the v20. The 19P will just lug the motor down (drop RPM's 400/500rpm) and give you poor performance and terrible fuel economy. That motor needs to be propped around 5500rpm.

I ran a seacraft 20MA with both a 19P and a 17P mirage plus with a 2.4L 225, 2.4L 200, and a 2.0L 150. I could turn the 19P about 5800 with the 200 and 225 (and just break 50mph) with the larger displacement motor. The seacraft is a lot lighter and faster hull than the v20. When I had a 2.0L 150hp motor on the exact same boat with a 17P mirage plus the boat could only hit 41mph (5500rpm)

You are getting decent performance with the 17P . . . Dial it in (raise the motor a hole or two) and fix your tach.

[randymbtech]

Got ya. I think your right. I am going to pick up a new tach this week, and start there.

[Airslot]

I owned a very similiar setup. 87v w/ 150 Black Max. Best prop for me was a 17p Rev 4 with the motor mounted one hole from the top. Loved that setup.

[reelapeelin]

What DIAMETER is your prop?...these Vs need a 15 1/4 to 15 1/2 inch diameter prop in my opinion...