Prop Diameter?

[JerEazy1]

Researching before testing out some new propeller possibilities in the OX66 150.

Currently running a 13.75x17 and not happy with the RPMs at 5100 when fully loaded down for fishing. So I've been looking at the enertia props for some better fuel efficiency and bite from a larger diameter.

My question is, how large of a diamaeter can I go on the 150? The lower unit is in the shop for refurb, so figured I would just ask. Top speed isn't my concern as. But most of the 4 blades and good 3 blades in been checking range from 14.75 - 16 in diamaeter.

Thanks!

[99yam40]

if you go larger diameter you will need to drop pitch that much more to get RPM up
if you can only get 5100 with that prop, going bigger is not going to get more RPM

[JerEazy1]

Yep - thank you

My thought was a 15p which would raise the RPMs about 400 - diameter increase of .75 to 1" would take off 100 of that. To put me at about 5400 for the heavy load - 5500 on the lighter days

The enertia prop (or quicksilver equivalent) also is said to move through the water easier based on thinner blades and bettter build. So the increase in diameter isn't a drastic if any drop in RPMs

My max diameter question was more for curiousity than usage.

[boscoe99]

Max diameter for your gear case is 15.75".

[Captn Dave]

Inertia or Q3 props are great props.
I would email Ken at Propgods. He dialed me in perfectly the first time.

I was running a Yamaha M 13 1/4 X 17 with a 150 carbed engine
and now running a Q3 14.5 X 17 with a 200 OX66.

The hole shot is a lot better and it rarely ventilates in turns now.

[JerEazy1]

Inertia or Q3 props are great props.
I would email Ken at Propgods. He dialed me in perfectly the first time.

I was running a Yamaha M 13 1/4 X 17 with a 150 carbed engine
and now running a Q3 14.5 X 17 with a 200 OX66.

The hole shot is a lot better and it rarely ventilates in turns now.

Ken is local to me luckily. So him and I have been bouncing around the idea of the Q3 16 pitch which is a 15 diameter, should get the better bite and hole shot but because of how they are built the increase diameter wont negatively effect the RPMs. He does a weekend trial for $30 that I'm going to set up once i get my lower unit back! (but this has given me opportunities to address some cosmetic and electrical stuff)

If the 16 isn't quite right then might have to step down into the 15 pitch which i believe is 14.75 on the diameter.

And thank you Bosco on the 15.75 figure!

[Jason2tpa]

Check yamaha performance bulletins. There might be one with a 150hp on a hull similar to design and weight as your hull.

https://yamahaoutboards.com/en-us/ho...ance-bulletins

[99yam40]

Jason, have you looked at that web site?
they have changed things up and show only 4 strokes now.

he is already on the right track with the help he is getting

[Jason2tpa]

Jason, have you looked at that web site?
they have changed things up and show only 4 strokes now.

he is already on the right track with the help he is getting

Yes. But you can also search through archived bulletins by doing a google search with your model/year engine. It takes a little more time to find what you're looking for if the bulletin exists, but they are available.

[99yam40]

are you saying you can find those old one on that web site?

[Jason2tpa]

are you saying you can find those old one on that web site?

No. Take a look again at my post as to how to find the bulletins.

[99yam40]

then why post a link to the place that does not send them to a place to find the info?

I would like a link to the web site that has the old ones

[Jason2tpa]

then why post a link to the place that does not send then to a place to find the info?

Yam must of recently changed the bulletin website. Didn't know this until you mentioned it. Thanks for heads up.

I would like a link to the web site that has the old ones

You can also search through archived bulletins by doing a google search with your model/year engine.

[99yam40]

see if you can find one for my C40TLRX
I cannot seem to find on using google