Whaler Central - Boston Whaler Boat Information and Photos

Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 15 cc 70hp yamaha prop size?

Posted by hank on 02/26/08 - 2:30 PM

I have a 1983 15 CC with the original 70hp 2-stroke Yamaha. Currently using a 19-k aluminum prop. I have seen others using a 17 pitch prop......what is the best choice for top speed?

Posted by ioptfm on 02/26/08 - 6:01 PM

Try this site. They have very good information and options.
http://www.piranha.com/

Posted by Phil T on 02/26/08 - 6:09 PM

Hank -

Welcome to WC.

To help you, please tell us more information. Specifically, what RPM and speed (mph) do you get at Wide Open Throttle (WOT). What holes are used to mount the engine. Is it sitting on the transom or are the top bolts in the 2nd ,3rd ,4t holes?

How much weight do you run with on average?

All this information will help us get you dialed in.

Posted by hank on 02/28/08 - 6:02 PM

Thanks for info guys, I'll have to wait until spring to get the rpm reading.....we should be boating here in another two months or so hopefully!

Posted by Tom W Clark on 02/28/08 - 7:19 PM

Do not use a plastic prop like the Piranha, those things are crap.

Phil offers some good advice. No good recommendations can be made without some performance data baseline.

We will also need to know what the manufacturer's recommended wide open throttle (WOT) range is as well as the gear ratio of the lower unit for the motor. Both these items can be found in your outboard owner's manual.

Edited by Tom W Clark on 02/28/08 - 7:20 PM