Prop size on a F60 Yamaha - 4.55 Quintrex Coastrunner

Post Reply
Posts: 278
Joined: Sun Jul 24, 2011 8:37 pm
Location: Katherine

Prop size on a F60 Yamaha - 4.55 Quintrex Coastrunner

Post by garrynt » Tue May 04, 2021 7:07 pm

Have done a bit of research of late & there never seems to be a resolution with Prop Sizes / speed/ etc

My usual prop is a 11 5/8 X 11G Alloy (standard 60 Yam)
WOT 5400rpm 41kmh on almost 4 trim (if I go to 5 it sucks air)

Spare prop is 11 5/8 X12G Alloy
WOT 6000rmp 43kmh on 4 trim
will cruise on 33kms at 4400rpm

Logic tells me that swapping to higher pitch 12, should of made WOT less than 5400 (ie should of been harder to get there), but it got better to about max 6000 - 6100 rpms. I only gained 2kms per hr more & it spins faster. Pickup is way better to get on a plane.

Boat 2000 Quintrex Coast runner 4.55 with full windscreen. Alloy prop cause I ding them.
I raised my motor up years ago and cannot recall what increase I got at that time, but it was better.
My top plate on yamaha is out of water by an inch. Cavitation plate still under water.
But maybe I need to drop it back?

Mate has a Stacer 4.55 side console with yam f60 & same 11 5/8 X 11 pitch prop & he gets 52kmh WOT

I know Its holden & fords all over again

* So therefore Should I go back to the 11pitch & cruise at just under my WOT which is way under the 6000 max rpms at 5400 to get better speed & economy.

What other prop options do others have, I'd like to try smaller / bigger props to find the happy medium for my boat, so are looking for what you have on similar size boats / motors to narrow my many choices.

Pic is motor at 4 trim angle, best speed before it sucks air.
You do not have the required permissions to view the files attached to this post.

User avatar
Matt Flynn
Site Administrator
Site Administrator
Posts: 14972
Joined: Thu Jan 01, 1970 9:30 am
Location: Somewhat Southerly

Re: Prop size on a F60 Yamaha - 4.55 Quintrex Coastrunner

Post by Matt Flynn » Wed May 05, 2021 10:52 am

Can speak from experience as I did several prop changes and engine height adjustments trying to get a new but under-performing 90hp engine to go.

Having a setup that produces lower revs than within spec at WOT is not good for an outboard, it makes them work harder. Best to have it running in spec and probably slightly at the upper end within the range in my opinion, because in the hot tropics you don't want an outboard working hard on long runs up and down rivers and along the coast. Outboard motors like to rev, although this probably applies more to 2-strokes.

Would be good to hear a marine mechanic's opinion.

Post Reply
  • Similar Topics
    Last post

Return to “Boats, Motors, Vehicles & Trailers”