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Yamaha F40 prop question
Brooksinct	#1  Posted on 07/20/11 - 5:38 AM
Member Personal Page Posts: 114 Comments: 0 Joined: 05/04/11	Well I finally bit the bullet and bought a new F40 yamaha. I am trying to decide what prop to run. The dealer said 10x15. I usually find myself loaded almost to capacity and I would like to be able to pull a wakeboarder every once in a while. My previous setup was a 1977 evinrude 35hp with a 10x13 and would like to be comperable with that. Any help would be great. Thanks
Tom W Clark	#2  Posted on 07/20/11 - 6:51 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	It would helpful if you told us what boat this motor is on. I makes a profound difference.
Brooksinct	#3  Posted on 07/20/11 - 7:26 AM
Member Personal Page Posts: 114 Comments: 0 Joined: 05/04/11	Sorry it is an 82 13 sport. I just figured that most people look at others personal pages.
Tom W Clark	#4  Posted on 07/20/11 - 7:40 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Never assume that. In fact, never assume people even read the subject line. All the information relevant to your question should be included in your actual post, even if it seems redundant or you think everybody already knows. Assume nothing. Propeller sizing depends on several things including the gear ratio of the outboard and its recommended WOT operating range. What propeller works on one motor has nothing to do with what works on a different motor. The Yamaha F40 has a 2:1 gear ratio and a WOT range of 5000-6000 RPM. If we assume a 1982 Sport 13 is capable of 36 MPH with a 40 HP motor, that suggests you would need about a 14" pitch prop.
Brooksinct	#5  Posted on 07/21/11 - 4:39 AM
Member Personal Page Posts: 114 Comments: 0 Joined: 05/04/11	Thank you for your help. Is there anyone who has this boat/ engine combo that has any comments? The dealer only has in stock a 10x13 and a 10x15. I dont know which to take for now.
blindeman	#6  Posted on 07/21/11 - 4:58 AM
Member Personal Page Posts: 182 Comments: 2 Joined: 07/28/08	Man, I'm about to install a 14 pitch on my C40 this weekend. I can tell you how it works out Sunday night. But, I'm going from a 9 pitch due to the motor having previously been used on a pontoon boat. From the research I've done, and an assist from Tom W. via a propeller calculator, I think a 14 pitch is the way to go. Of course, every application is slightly different. But, it's likely a good place to start. Bruce Lindeman 1992 Sport 13
Tom W Clark	#7  Posted on 07/21/11 - 10:15 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Yamaha does not offer any 10" x 13" propeller so I am not sure what the dealer is offering you there. Yamaha does make one 10" x 15" prop and it is an aluminum three blade. I do not recommend that propeller. If you want a Yamaha prop, I strongly recommend the Yamaha 10-1/2" x 13" Performance 3-Blade, part # MAR-GYT3B-03-13. This same propeller is also sold as the Stiletto Triad 3.5 and the Turbo Hot Shot 3.5 Edited by Tom W Clark on 07/24/11 - 5:14 PM
Brooksinct	#8  Posted on 07/24/11 - 11:17 AM
Member Personal Page Posts: 114 Comments: 0 Joined: 05/04/11	Si I installed the engine and brought it back to the dealer for the first run. The got the 6H5-45958-00-EL in stock which is a 10 1/4x14 and gladly traded my 10x15 for it. This prop allows me to hit 5700 rpms with just me and 15 gallons of gas in the boat. It also was able to get myself and 5 adults, 1 baby, 2 coolers and 15 gallons of gas on plane and when trimmed out I was able to get 5100 rpms out of it. I will see how this prop does when towing something but so far it seems to be perfect. Thanks for the help.