Need Prop help

[allen456]

Looking to replace the prop on my 200ccp with a 1981 johnson 175.  The current prop is from what i can tell is a 15 1/4 x 19.  Seems a little slow out of the hole and struggles with more than two people.  I know the engine can use a tune up and that is already scheduled.  Currently with WOT,  two people and lite gear, the boat tops out at approx 36-37 mph, is this about right and 5200 rpm?  Thanks for the help.

[Capt. Bob]

Start here for theory.http://www.theoutboardwizard.bizhosting.com/how_to_choose_the_correct_propeller.html

Here are some recomendations from OMC http://www.theoutboardwizard.com/Outboard_Propellers_OMC_BRP_Props.html

This will get you started. If you have a service manual for your 81, it will list the engine's max operational range say 4500 to 5500
RPM. Your goal is fit within that range. It appears you have done that (you need to confirm this range) and seem to be within the speed range this prop probably generates though I'd have guessed it would run 40mph+. Therefore I'd tune it up first and see how she runs before shelling out coin for a prop.
Good luck.

[Aswaff400]

how often do you use the boat? the previous owner of my osprey didnt use the boat for a year, i drained the gas and ran about 25 gallons through it within a few days... when i first used the boat, i only got upto 31 mph and 5200 rpm, now i hit 38 mph, at 5800 rpm, and i've seen almost 43 mph goin with the wind at 6000 rpm... and thats with a 112!

[allen456]

how often do you use the boat? the previous owner of my osprey didnt use the boat for a year, i drained the gas and ran about 25 gallons through it within a few days... when i first used the boat, i only got upto 31 mph and 5200 rpm, now i hit 38 mph, at 5800 rpm, and i've seen almost 43 mph goin with the wind at 6000 rpm... and thats with a 112!

I run the boat as often as I can.  When i received the boat it had sat in the boat house for 15 yrs and maybe used 10-12 times.  I rebuilt the starter and cleaned and adjusted the carbs.  I have run approx 150 gallons thru it since I got the boat.  I istalled a new tach this past weekend and hopefully will have more accurate readings.  Thanks for the input.  You almost have to have a PHD in astrophysics to choose the correct prop.  I am liking the idea of the ProPulse prop until I find the correct diameter/pitch in a 4 blade.  http://www.foreandaftmarine.com/PP-4901.htm
I can buy things at dealer cost, but still don't want to through money away until I find the correct prop for me.  When I finally decide on the best set up, I will get a stainless prop.