need advice on prop pitch and diameter

[shane Rodgers]

I have just bought a 2009 60hp yamaha enduro..boat is 4.6 mtr tabs jumbo... My problem I am having is from half throttle too full throttle the engine does not have any feeling of acceleration very flat... Also fuel economy is just over 1 km/litre... Max speed 40 k/pH... What size propeller would you recommend. Too get acceleration from half throttle too full????
Size of prop now is 13 5/8 x13 - k
Recommendations??? Thankyou.

[almetelo]

1st thing you need to do get a tachometer (can even be a cheap inductive tach)

Your motor must run at 5500 rpm's (or near) at WOT with usually load (Persons, fuel, gear etc etc)

To me looks like you have a small pitch prop (13) for your boat (maybe not) all depends of load on boat.

You must read some articles about selecting the correct prop.

That motors 60 Enduro usually are reliable but fuel economy if far from be its best point however thats way to much... (at WOT fuel consumption may be +/- 65L/h)

If all is good on the motor I would test a 17K pitch prop (to test you'll need a tach) and not try to guess or choose the prop that just will give you better top speed

Try to have a 15K or a 17K pitch prop borrowed for testing before spend you money on a new and wrong (inadequate) prop for your needs

Good luck

[almetelo]

By the way....

A 2009 60 enduro ? are you sure it a 2009 motor?

Where are you located (country)?

[shane Rodgers]

I am in Australia. Is 2009 60hp enduro.. Top speed. Is nor nesasary factor.. The fuel consumption is more what I would like too achieve..

[almetelo]

OK

On my country and most EUropean countries Yamaha 2 stroke are not on sale for more than 10 years

Just for commercial use (exactly the guys that will need better fuel economy and will not buy them)

However 60 enduro was and still is very popular here

The only down side is the fuel consumption.

Good luck with your motor

[shane Rodgers]

I am in Australia. Is 2009 60hp enduro.. Top speed. Is not nesasary factor.. The fuel consumption is more what I would like too achieve..

yes it is a (13)K
Thankyou very much your advice is valuable too me...

[boscoe99]

What is needed is your wide open throttle RPM with the boat loaded as you would use it, with the engine trimmed up to the point of maximum efficiency. As Almetelo notes, it should be at or near 5500 RPM.

What is the style of the boat. I am in the US and don't recognize a "tabs jumbo", whatever that may be.

Wide open throttle is used to choose the most practical propeller, even if you never ever run the boat at wide open throttle.

[almetelo]

(at WOT fuel consumption may be +/- 65L/h)

What I was thinking!?!?!?

(not intended to scare you)

65L/h is +/- the fuel consumption of a 150 at WOT

Your motor must be +/- 28L/h at WOT (can check later when at home)

[99yam40]

Rule of thumb is usually 10% of the hp in gallons Per Hour at WOT.
so a 60 would be around 6 GPH
Not sure in the metric system though.

Most people never run at WOT except to get up on plane.

Best fuel economy is usually somewhere between 3500 to 4500 on most rigs depending on what boat, prop, and load you are pushing
Along with the way it is set up.
Pushing a barge fully loaded is a lot different than a planing hull up on top

Too much prop and you are lugging the motor at all RPMs, too small and you stand the chance of over reving the motor.
Correct prop getting your motor to 5500 at WOT will get you the best performance and economy but not at WOT

[boscoe99]

What about the British system of furlongs per fortnight?

FFF system - Wikipedia, the free encyclopedia

On the assumption that the motor is running well and creating rated horsepower then you might want to go to the Yamaha US website and look at their performance bulletins, trying to find a 60 HP two stroke that is being tested on a boat that is similar to yours. Whatever propeller was used during the PB test is usually about two inches to much pitch. So, for real world usage, try a propeller that has two inches less pitch than was used for the PB.

For instance here is a typical PB. Note the fuel burn of 6 GPH at WOT which correlates with what 99yam said. Also that the most efficient running RPM is 3500 which is also what he said. You foreign guys can do the conversion into whatever mumbo jumbo units of measure that you use.

[99yam40]

Are the PB prop choices really not correct for most?

I cannot tell on my C40 on an xpess 16SV because they do not list a 40 anymore.
Seems like I remember seeing some before listing the 40s but they are not anywhere to be found now.
I have been wearing down my prop in the shallow muddy/sandy bottom waters I run in most of the time and the WOT RPM has risen a few hundred RPMs .
Time to have the 3 blade SS Ballistic 10 1/8" X 13" rebuilt.
May just pick up a new one and keep old one to have a spare

It originally ran right at 5500 and I thought the PB listed that size and pitch prop for my rig

Edit I was wrong from what I have written(posted) before the PB gave the prop as 10 5/8" X 12" for the 40

Anyway here is a link to where you can look for rigs like you are running or close to it .
http://yamahaoutboards.com/owner-res...ance-bulletins

[boscoe99]

Are the PB prop choices really not correct for most?

I cannot tell on my C40 on an xpess 16SV because they do not list a 40 anymore.
Seems like I remember seeing some before listing the 40s but they are not anywhere to be found now.
I have been wearing down my prop in the shallow muddy/sandy bottom waters I run in most of the time and the WOT RPM has risen a few hundred RPMs .
Time to have the 3 blade SS Ballistic 10 1/8" X 13" rebuilt.
May just pick up a new one and keep old one to have a spare

It originally ran right at 5500 and I thought the PB listed that size and pitch prop for my rig

The boats as tested for PB reports are new and as light as they will ever be. Most PB boats don't use full fuel, won't have more than two guys on board, and won't be equipped for a days fishing trip.

So, the propeller used in the PB report may be OK for the boat in its brand new lightly loaded configuration, but once the boat is in service and loaded it almost always will be over pitched by about two inches. As a rule of thumb.

Lowest HP I can find today for an Xpress boat is a 50. It used a 10 5/8 X 12 pitch. Not sure how the boat compares to yours. In a real world that boat and motor configuration would need about a 10 pitch. If you are using a 13 pitch with a 40 HP I presume you must have a much lighter boat.

[99yam40]

I try to keep it as light as possible to get across some shallow flats while poling
I did eliminate the *****ing motor with bracket on the front, battery for *****ing motor, and turned the live well into dry storage. But did mount an aluminum polling platform on the back though.
Only 6 gal tank, side console, removable seats, 1 battery, ice chest with ice and drinks, tackle boxes, Push pole,and fishing rods.
Does well with 2 people, but 3 grown adults does strain to get on top.
Once on plane it does Ok even WOT RPM are good
I do not do that very ofter as 3 people lure fishing out of a 16' boat can get dangerous even with me on the poling platform.

Closer to this one http://yamahaoutboards.com/sites/def...sv16-50tlr.pdf

[almetelo]

Rule of thumb is usually 10% of the hp in gallons Per Hour at WOT.
so a 60 would be around 6 GPH
Not sure in the metric system though.

Most people never run at WOT except to get up on plane.

This rule of 10% of HP works really good for 2 strks most of the time (I guess even for 4 strokes but just at WOT as fuel consumption is +/- the same as 2 strk (at WOT)

I would like to run more time at WOT but gas is very expensive here and I'll do it just for a couple of min on my F100 and not all the ways I go out (not even close) But back in 1995 when bought my 30x3 that motor just had idle and WOT I had 16 at the time, gas was cheap, money wasn´t from my wallet and economy/wages and bussiness was much better than now.

according SM 60 enduro at WOT have fuel consumption is 25.5L (6.7 Gal) but my experience show that is always more than the max fuel consumption annouced by the manufacturer (is like on cars, is almost impossible get the fuel consumption the manufacturer annouce) Tests must be done at optimal conditions.

The 60F / C60 have better fuel consumption according SM 22L/h (5.8 Gal)