iboats - The #1 Store For Everything Boating
 
  #1  
Old May 24th, 2009, 10:27 AM
LEGENDRIDER LEGENDRIDER is offline
Cadet
 
Join Date: May 2009
Posts: 1
Default correct pitch for yamaha f40 pontoon app

Hi all,

Just curious to the correct prop for my Yamaha F40 which os on a 18ft pontoon, I suspect the one we have is not correctas it only reaches about 3900 rpm at WOT

Thanking you in advance
Reply With Quote
  #2  
Old May 24th, 2009, 04:00 PM
Silvertip Silvertip is online now
Supreme Mariner
 
Join Date: Sep 2003
Location: Midwest
Posts: 15,221
Default Re: correct pitch for yamaha f40 pontoon app

What pitch is the current prop. Engine running OK? Did it ever rev beyond 3900?
Reply With Quote
  #3  
Old May 24th, 2009, 07:04 PM
hwsiii's Avatar
hwsiii hwsiii is online now
Lieutenant Commander
 
Join Date: Jan 2009
Location: Pascagoula, MS
Posts: 1,983
Send a message via Yahoo to hwsiii
Default Re: correct pitch for yamaha f40 pontoon app

Legend, we welcome you to the forum and hope to be able to help you with the questions you need answers to. If you will supply us with the answers to the questions listed below we will have everything we need to help you with your quest, in most cases.

Boat and Motor



H
Reply With Quote
  #4  
Old May 24th, 2009, 08:40 PM
steelespike steelespike is offline
Fleet Admiral
 
Join Date: Apr 2002
Posts: 8,390
Default Re: correct pitch for yamaha f40 pontoon app

Prop size usually appears on the barrel or under the prop nut.
A one inch reduction in pitch will increase rpm ABOUT 200.
Assuming the max rpm of the F40 is 6,000 you would need about a 10"
reduction in pitch. If your allready at say 15" You have other problems.
You may still need a prop reduction but the motor may need a check up.
If you can get us the prop size,and max rpm and speed we can tell better
whats up.
Reply With Quote
  #5  
Old May 24th, 2009, 09:36 PM
Silvertip Silvertip is online now
Supreme Mariner
 
Join Date: Sep 2003
Location: Midwest
Posts: 15,221
Default Re: correct pitch for yamaha f40 pontoon app

A 40 four stroke on an 18 foot pontoon should do well with a 14x 11. If you have a prop in that range, there is something wrong either the boat or the engine. Even a 60 HP 4S runs a 14 x 11. My 18 foot Misty Harbor is powered by a 40 Suzy 4S and it runs an 11 pitch at 5800. I would start by verifying that the throttle linkage is adjusted correctly and that it is opening fully at wide open throttle.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Yamaha F40 Won't go into Reverse bobby541 Yamaha & Suzuki Outboards 1 July 7th, 2008 08:13 AM
F40 Yamaha No Power RMunger Yamaha & Suzuki Outboards 3 May 30th, 2007 09:58 AM
Yamaha F40 Painting newf1 Yamaha & Suzuki Outboards 1 July 23rd, 2006 01:32 PM
Yamaha F40 2004 DCB2 Yamaha & Suzuki Outboards 4 April 2nd, 2005 04:40 PM
Stupid mistake - F40 Yamaha mallardjusted Yamaha & Suzuki Outboards 11 March 2nd, 2005 11:43 AM

iboats Forum Directory
Over 100,000 forum posts organized by topic
Outboard Motor Topics
Mercury Outboards
Johnson Outboards
Evinrude Outboards
Force Outboards
Yamaha Outboards
Mariner Outboards
Suzuki Outboards
Honda Outboards
Chrysler Outboards
Tohatsu Outboards
Nissan Outboards
Outboard Motors: non-repair
Vintage Outboards

I/O and Inboard Topics
MerCruiser
OMC I/O, Inboard
Volvo Penta

Propeller Help
Boat Propellers

Boat Repair and Products
Boat Building and Repair
Fiberglass Boat Repair
Marine Electronics
Boat Trailers and Towing
Boat Names
Boat Covers
Boat Parts

Boating Activities Talk
Boating Topics and Questions
Boating Activities and Destinations
Boating Blunders
Boat Shows
Wakeboarding
Water Skiing

Fishing Discussions
Freshwater Fishing
Saltwater Fishing

Boat Type Topics
Aluminum Boats
Bass Boats
Bowrider Boats
Center Console Boats
Cruiser Boats
Cuddy Cabin Boats
Deckboats
Fishing Boats
Fish and Ski Boats
Houseboats
Jet Boats
Jon Boats
Pontoon Boats
Powerboats
PWC Forum
Ski Boats
New Boats
Used Boats

Boat Manufacturers
Boats 250+ Manufacturers
Bayliner Boats
Sea Ray Boats
Zodiac Boats



Outboards

Power Heads

Lower Units

Propellers

Inflatable Boats

Boat Manuals

Engine Parts

All times are GMT -4. The time now is 09:27 PM.