Prop on f100 yamaha

[Hoffmann]

My prop says 13x19-k
What do the numbers stand for.
It is tore up bad and would like to replace it.
If I want more top end which number should be different and up or down?
If I want to go slower at idle which number should change and up or down?

 

[pine island fred]

Re: Prop on f100 yamaha

13 in. diameter, 19 in. pitch. Sound like an awful lot of pitch for a 100 hp. What was the max RPM it would turn? When I got my F115, I installed a shiny SS of the same size. Would only spin up to 5400 and made oil. Dropped down to a 13 X 15 and the motor spins to 6200 and quit making oil. Was a big mistake/ investment. Been tripping over it in my shed for 4 years now. I do pick it up occasionally and wipe it down. Nice pristine paperweight!!! regards FRED

 

[Hoffmann]

Re: Prop on f100 yamaha

what do you mean by "made oil"
The prop that is on my 13x19-k I believe is factory yamaha aluminum prop, I run trot line with the boat and would like to go a little slower at idle if possible. I will have to check the Rpm's but it sounds like it's turning some high r's!

 

[steelespike]

Re: Prop on f100 yamaha

Some 4 strokes will "make oil" if operated below its operating rpm range.
The oil level actually increases from the accumulation of condensation in the oil.
Sometimes recomended to run wide open for a while at the end of the day to get rid of the condensation.We need your boat description, and present max rpm and speed to tell about your 19" prop. 13" X 19" ,diameter X pitch. Pitch, is the key number,diameter simply follows the design. The motor must be able to operate within its designed wot(wide open throttle) rpm with a light load. To keep things simple higher pitch(number) lowers rpm lower pitch increases rpm.Assuming the motor can operate at its max rpm a higher number gives more speed less power like overdrive on a car, lower number gives more power less speed. Most likely the 19 is too much
If you go to lower number your trolling speed will reduce slightlyIf your motor is struggling to make rpm a lower pitch may actually improve your top end.
The best thing to do would be to get the prop repaired if possible and get a fresh set of performance numbers.

 

[connemaraisland]

Re: Prop on f100 yamaha

I have a F100 on a 19ft deckboat and it has tons of kilometers on it, it runs the best with a 131/4x 17 prop. It turns 5900 rpms wide open and my normal cruise is 4200-4600 rpm. Awesome engine and I am in the business and have never seen a F100 that could benefit a prop larger than that unless it was maybe on a tiny boat - Bob

 

[SparkieBoat]

Re: Prop on f100 yamaha

the most common reason for making oil is a stuck open t-stat..yammy has way over priced their t-stats..they are shooting themselves in the foot with the practice of way over pricing parts. you should pitch your motor to run 5500-5800 RPMs. Rodbolt told me to not let mine get over 6K EVER. I have a 2003 F115. Hoff we need your current WOT RPMs and speed to help you determine pitch.