20' cc with 150 Yamaha- ? mph

Magothy1 · #1 08-19-2009, 10:37 PM

I have an '86 20' cc with a 150 Yamaha, fuel injected 2 stroke, it runs 40 mph with just me and full fuel, seems as tho it ought to do a bit better, running a 14x17 prop now.
Tach has quit, I think it was turning around 5500 rpm. Anyone do lots better with a similar setup ?

Bigshrimpin · #2 08-20-2009, 09:37 AM

You motor might be able to come up a few holes . . . which minimizes drag (increases RPM/speed).

Caymanboy · #3 08-20-2009, 11:26 PM

Need more info, T Top? Bimini top? Etc? I run a 1970 (light boat) with a 200hp 2 strk Yami, 50 kts, but I have to work at it, trim, water, etc.

eggsuckindog · #4 08-21-2009, 02:15 AM

Thats about right I would think, I have a 200 with a T Top and right at 50

#5 08-22-2009, 08:41 PM

I run a 1970 20 with a 175 2 stroke Yamaha on a bracket. I get about 49 loaded to fish with 2 people on board.

Magothy1 · #6 08-22-2009, 10:48 PM

Thanks for all that, I'll look to see about raising it, I can't recall right now where the cavitation plate is relative to the bottom. From the other posts it looks as tho it's in the ballpark. When I get the tach back to working I might try another prop with a little more pitch. It did well with five big adults, all 200 lb plus, jumped right out and ran well. It does have a T-top.
Thanks again,
Steve

jammingator · #7 08-24-2009, 02:01 PM

My '75 with a 2003 Yamaha VMax and T-Top will run 48 mph with me, my wife, 2 young kids and half a tank of fuel. Fun, fun!