rpm question

[CHRIS]

2001 200hp ox66 saltwater series. book says optium range should be 4500 to 5500. i barely hit 5000 at full throttle on flat water. i have only hit 32 mph on gps. boat is a 2001 w/a seapro.
prop is a painted ss 19m. i have tilted motor up till she bounces too much. would i benefit by putting on a 17 true ss prop? friend of mine with a 23ft cc and 200 suzuki hit 53mph at 5500 rpm.
i thought i should at least hit 40mph or am i dreaming.

[jb123]

you can play with props,21 is usually a good AVERAGE choice, but many wheels are cupped,ported differently, just something to play with and find what works best for your needs. you can also lift motor on transom a hole or 2 for added performance, as long as you get adequate waterflow.

[fish addict]

I have a '89 200 hp 2stroke and wondering what the manual says is the optimum rpm while crusing. tks

[Ken]

Chris,
You are already at mid-range with your existing prop. You might squeeze out another one or two mph by dropping to 17 inch pitch, but that will put you into the upper range of rpm - I personally like to run max rpm right at mid-range.
Stainless steel is stainless steel no matter what color it is painted.
How does your boat weight compare to your friends boat? A few hundred pounds can make a big difference.
Go to another forum at www.maverickboats.com and look up Marcus - aka "Funky Monkey" - he is the Power Tech prop rep in Louisiana - he has helped a lot of boat owners get the max out of their motors with the right prop selection.
Good luck,
Ken K

[Ken]

fish addict,
What do you mean by "optimum rpm while cruising"?
If you mean max hp at what rpm, then it would probably be mid-range of 4500-5500 rpm (the owners manual gives max range - go to www.yamahapubs.com for an owners manual).
If you mean max fuel economy, then you would have to install a fuel management system to determine max mpg - that is going to be a function of the outboard and the planing characteristic of the boat.
Before I bought my 2000 Pathfinder, I was able to compare performance data with different motors.
This is usually done by the manufacturer of the boat. For my boat, which is a cc and weighs around 1100 pounds, the max fuel economy for the Yamaha C115 is at 4000 rpm (34 mph) - max rpm is 5200 which gives me 46 mph.
Hope this helps,
Ken K