Author Topic: Propping a Yamaha F-70  (Read 1232 times)

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Online Chief of the Boat

Propping a Yamaha F-70
« on: October 07, 2012, 02:12:08 PM »
I installed the network cables from the F-70 to overlay the engine data on the Lowrance HDS-5 Gen II.  I took the boat out yesterday and here is the data I recorded with my current prop a Solas Titan 3 Blade Stainless 13.75" dia. X 13" pitch.  
RPM   GPH   MPH
4102   3.22   15.7
4363   3.43   18.6
4539   3.57   19.3
4703   3.83   21.2
4910   4.31   23.0
5008   4.46   24.3
5203   4.94   25.5
5434   5.21   26.7
5734   5.86   28.6
5875   5.94   29.6
The F-70 is a great motor that is basically a high reving 50, I am concerned that I am not hitting at least 6000 rpm at WOT(rpm range 5300-6300).  Grizzle is offered to let me borrow his Powertech clevered S/S prop.  I plan on spending a day at Kitsap Lake and do some prop testing with my two other props and Grizzle's, I also will be adjusting the Smart Tab settings.
Terry

« Last Edit: October 07, 2012, 02:52:38 PM by Chief of the Boat »
1994 Sea Explorer 1511 loves whitecaps 2010 Yamaha F-70 2012 Yamaha F-8 with a  Fixed SaltBoss Bracket Lowrance HDS-5 & 7 Gen 2 Standard Horizon Fixed VHF 2150 with AIS

Offline redbaronace

Re: Propping a Yamaha F-70
« Reply #1 on: October 07, 2012, 04:07:13 PM »
The guy at Three Rivers Marine said that a range between 5800 and 6000 is where the RPMS should be on my 115 Yamaha.
 

Offline Grizzle

Re: Propping a Yamaha F-70
« Reply #2 on: October 07, 2012, 05:06:46 PM »
Nice Data!  I'm guessing the 13" powertech will get you to the redline since it does on mine and we run heavier.  But you sure running nice there with a 5000 cruise @ 24mph and 5.4mpg.
Brook Stockton - My Boat: Mighty Molly - The Fish Monger - Arima SeaChaser 16 - Soft SkipTower and "The Rack"

SALTBOSS™ MARINE - Offshore Marine Products & Fabrication - http://saltbossmarine.com - brook@saltbossmarine.com - 206-953-SALT (7258)

Offline Markshoreline

Re: Propping a Yamaha F-70
« Reply #3 on: October 07, 2012, 08:00:55 PM »
Chief, on my new 115 the max RPM's have steadily increased and now are at 6000 with the same prop that originally would only put out about 5300 rpm.  I guess it is getting broken in and a bit looser.
How many hours on yours right now?
2002 Sea Ranger HT 21, Yamaha 150, Yamaha 9.9

Online Chief of the Boat

Re: Propping a Yamaha F-70
« Reply #4 on: October 08, 2012, 06:31:39 AM »
It has 163 hours on it.
1994 Sea Explorer 1511 loves whitecaps 2010 Yamaha F-70 2012 Yamaha F-8 with a  Fixed SaltBoss Bracket Lowrance HDS-5 & 7 Gen 2 Standard Horizon Fixed VHF 2150 with AIS

Offline Markshoreline

Re: Propping a Yamaha F-70
« Reply #5 on: October 08, 2012, 09:32:27 PM »
Yours should be loosened up by now.

But you have to realize that 5875 is 98% of 6000. Pretty close and questionable cost benefit to buy a prop for 2%!

Mark
2002 Sea Ranger HT 21, Yamaha 150, Yamaha 9.9

Online Chief of the Boat

Re: Propping a Yamaha F-70
« Reply #6 on: November 29, 2012, 04:56:19 PM »
We sea trialed loves whitecaps last Saturday on Hood Canal with Brooks PowerTech prop and the new kicker bracket(Thanks Brook & Eric),  both performed flawlessly.  The Yamaha F-70 rpm range is 5300-6300, the two out of three rule I always use about asking for advice resulted in the three plus dealers telling me that 5800 rpm is fine.  The folks at PT props an American company in Louisiana were very persistent that 5800 is too low, you need to hit at least 6100.   The motor sounds awesome spooled up at 6300rpm, and has a great hole shot and does not porpoise when trimmed way up.  My American made PT prop arrived yesterday; it is a work of beauty like the SaltBoss stuff.  Got skunked crabbing.
 :applause:
Terry
1994 Sea Explorer 1511 loves whitecaps 2010 Yamaha F-70 2012 Yamaha F-8 with a  Fixed SaltBoss Bracket Lowrance HDS-5 & 7 Gen 2 Standard Horizon Fixed VHF 2150 with AIS

Offline Grizzle

Re: Propping a Yamaha F-70
« Reply #7 on: November 30, 2012, 07:30:02 AM »
 :cha:

Terry I'm glad the prop worked out for you.  It took a while for me to get used to hearing that motor howling back there when we're running hard but I love it.   That motor loves to spin up.   
« Last Edit: November 30, 2012, 04:41:15 PM by Grizzle »
Brook Stockton - My Boat: Mighty Molly - The Fish Monger - Arima SeaChaser 16 - Soft SkipTower and "The Rack"

SALTBOSS™ MARINE - Offshore Marine Products & Fabrication - http://saltbossmarine.com - brook@saltbossmarine.com - 206-953-SALT (7258)

Online Chief of the Boat

Re: Propping a Yamaha F-70
« Reply #8 on: December 02, 2012, 07:28:40 PM »
Looking at all the Yamaha performance bulletins and the minimum WOT rpm with a F-70 is 6100 on a pontoon boat.
1994 Sea Explorer 1511 loves whitecaps 2010 Yamaha F-70 2012 Yamaha F-8 with a  Fixed SaltBoss Bracket Lowrance HDS-5 & 7 Gen 2 Standard Horizon Fixed VHF 2150 with AIS