Quick and easy prop question

[CodyDawg]

How do I tell if my prop is 13.25 X 17?

[CodyDawg]

It is an 06 Yammy 115 4 stroke.

[marine_man]

You'll need to remove the cotter pin, castle nut and washer, remove the prop and look at the other side of the prop.

You could also look on the exterior of the prop hub.. but if you have a factory yamaha prop you'll need to remove the prop to find out for sure.

marine_man

[CodyDawg]

thanks. i will take it off tonite. it is actually set up for a merc prop (not that that matters).

[marine_man]

If it's a merc prop it'll probably be stamped on the hub on the exterior of the hub of the prop and you won't need to remove the prop to find out the pitch.. there should be a bunch of numbers stamped on the exterior hub (on the same axis as the prop shaft, viewable from the outside of the prop) with the last two numbers being something like 17P, which would mean 17 pitch.

marine_man

[Ralph Wiggum]

Quote:

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If it's a merc prop it'll probably be stamped on the hub on the exterior of the hub of the prop and you won't need to remove the prop to find out the pitch.. there should be a bunch of numbers stamped on the exterior hub (on the same axis as the prop shaft, viewable from the outside of the prop) with the last two numbers being something

like 17P, which would mean 21 pitch

.

marine_man

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Don't you mean that 17P would mean 17 pitch?

[marine_man]

Oops... yep.. that's correct.. I edited my post to switch the example to a 17P prop, but forgot to correct it.. thanks for the catch!

marine_man

[CodyDawg]

So I took that sucker off and it didnt say anything anywhere that looked like the diameter. It had 48-16986 and then 16P on the outside (it is a stainless, I want to get an aluminum). So I measured the tip of a blade to the closest piece of the motor straight above it when the blade was in the 12 oclock position and then from the same place to the tip of a blade in the 6 oclock position. the difference was exactly 13.25, so that is my theory and I am sticking to it....for now.

[BandB]

just an FYI if you are going from stainless to alum. you will need to pitch up because the stainless prop dose not flaten out under load like the alum. I beleive its pitch up some one correct me if I am wrong but I think its like 1 to 1.5 to get the same performance as the stainless (rpm's and mph). If you go to some of the bigger marine shops they will let you try out prop's to make shure you get the right one.

[cjac]

The boat makes a difference of course, but I run a 19P aluminum on my 115 Yammy.

CodyDawg: Are you switching because of performance? I could not find a stainless that performed well on that motor. Stainless prop for that motor weighs 13 lbs, that's a lot to turn. I got top end speed with one, but was still not hitting the RPMs I should have. Went another step down in pitch, and it was running darn near at redline, and if I trimmed up I was at redline. Also tried a few blade variations, but to no avail. Just curious more than anything.......

Thanks, Chris

[hoggs222]

My original prop from my 115 Yammy was stamped on top in between the blades. it said 17x??. & -3 or something. I just replaced it last weekend and didn't need to remove it to see the stamp.

[CodyDawg]

I want an aluminum for fishing Lac Seul. I have been really lucky up there, but I dont want to tempt fate. I can just see the irony....first year with stainless....whack big brown round one.....wreck lower unit. Also, I am really anxious to see the difference in performance. I did go up a pitch for aluminum. Everyone says how great stainless is, but on my last boat (Lund ProV), it made very, very little difference on top end (1/2 mph) and no discernable difference in hole shot.

[marine_man]

Quote:

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It had 48-16986 and then 16P on the outside

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The 16P means it's a 16 pitch prop... If I were to get an aluminum I'd probably go for a 15 pitch prop.

marine_man

[CodyDawg]

I thought you went the other way, to a 17. Because of flex, you need to grab more water. At least that is what my dealer told me.

[marine_man]

Oops... you're right... sorry about that...

Go for the 17... verify it by comparing your full throttle RPM reading to your engine's RPM range...

marine_man