Fuel Consumption guide for a 60hp 2 stroke outboad - predictions please

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Capt Popeye

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Hi ; Hoping to try out my latest boat which has a 60hp 2 stroke 3 cylinder outboard but am quite uncertain of the amount of fuel consumption per hour , its a petrol (auto mix engine ) , I should allow for

Anybody please give me any indication from their experience ; assume running at about half throttle , certainly not flat out

Proposing to carry 2 x 5ltr extra in small cans just in case

Hoping to do a coastal hop into Torquay Harbour berthing at the Visitor Pontoon , so want to do it easily and safely , without drama or RNLI ssistance

Thank you CP
 
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Weight and size of boat, shallow or deep v ?
I get around 7 mpg from a 50 4 stroke. I did 25l in 5 mins with a 200 2t.
Rib.net suggest 27 l/hr wot. 16 l/h at 4000 rpm for a 60 2t.
Image below is from another source
 

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Years Go I had an yamaha 30hp, 3 cylinder, 2 stroke with built in oil tank. That could use 2 gallons per hour of petrol when near full power on a displacement boat. Maybe double it for a 60hp?
Why not stay local and work some fuel consumption at certain revs, speed, etc? Spare 10 litres doesn't sound much.
 
A reasonable rule of thumb for traditional 4 petrol strokes of any kind is a gallon per 20Hp per hour.
A 2 stroke would be somewhat higher, probably 15Hp per hr.
 
Davy_S said:
My last Evinrude 60hp 3 pot 2T engine, pushing a 15ft Shetland sealark, would burn 25 litres per hour at just over three quarters throttle.
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pretty similar for my Shetland Family4 when it had a 50hp 2stroke, about 23 LPH or 5mpg. For a day out I would carry 80-100L.
Unless the motor is far too big for the boat, expect to be at the 60-70% throttle mark, rather than 50%, its not how 2strokes have their power bands, they really only work near the top end, unlike new 4 strokes
 
Very many thanks for ALL the replies and suggestions plus data ; Not sure if MY boat is a Semi Planing , Deep Vee hull, will try and post a photo of it ; Re furl consumption , as I understand it 2 strokes develop their power at high revs , so whats the approx fuel consumption at say quarter throttle which I guess will give me about 8 knots through the water ?

Thanks , did not appreciate the High fuel consumption in a 60hp Outbpard , so would like to get an idea of cruiing range before venturing out into the sea , local cruising limited to about 10 miles up river on a Good High tide , with a long wait between high tides if the muddy bottom appears too quickly .DSCN1057.JPG
 
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thats a planing hull. Between 6-14 knots you will be burning petrol to just push a massive bow wave around. The outboard won't like prolonged low revs and may keep fouling the spark plugs.
I've no idea about low rev mpg, because I've never tried a big 2t at long term low revs, that's where 4strokes do best
 
The rule of thumb was one gallon per hour per ten horsepower, half that for a four stroke, as alluded above.

Apologies if teaching you to suck eggs:
  • Your greatest endurance will be at a speed whereby the boat is just planing comfortably and you will be burning fuel much more parsimoniously than at w.o.t.
  • Your best MPG will thus be on a flat sea at something like 12 kt, faster if you are stemming a fast tide. Add waves or enthusiasm and you will shorten that endurance towards the rule of thumb and range perhaps more so.
  • If possible, open the throttle full to get onto the plane quickly, then back off until it is just still planing flat.
  • You can fiddle with the tilt angle of the motor (preferably with hydraulic trim) to get the best economy, but this is affected by sea state.
  • I'd carry a good 20L of spare fuel in a proper outboard tank with hose. Enough to get to a harbour/ safe beach if the main tank or its plumbing failed. Refilling with cans can be a nightmare at sea.
  • Rotate the tanks so that the fuel doesn't go off.
 
Iliade said:
The rule of thumb was one gallon per hour per ten horsepower, half that for a four stroke, as alluded above.

Apologies if teaching you to suck eggs:
  • Your greatest endurance will be at a speed whereby the boat is just planing comfortably and you will be burning fuel much more parsimoniously than at w.o.t.
  • Your best MPG will thus be on a flat sea at something like 12 kt, faster if you are stemming a fast tide. Add waves or enthusiasm and you will shorten that endurance towards the rule of thumb and range perhaps more so.
  • If possible, open the throttle full to get onto the plane quickly, then back off until it is just still planing flat.
  • You can fiddle with the tilt angle of the motor (preferably with hydraulic trim) to get the best economy, but this is affected by sea state.
  • I'd carry a good 20L of spare fuel in a proper outboard tank with hose. Enough to get to a harbour/ safe beach if the main tank or its plumbing failed. Refilling with cans can be a nightmare at sea.
  • Rotate the tanks so that the fuel doesn't go off.
Click to expand...

Hi there lliade many thanks for that info ; its new to me ; the only bigish ob I have ever had was a 50hp 2 stroke on a 13ft speedboat , that planed quite quickly the boat was very light so fuel ecconomy was good ; this craft with its 60hp ob is new terrirory to me ; what with the Covid Restrictions etc plus Harbour Master rules about boating the last nearly 2 years its a rather prolonged intro to such boating ; hence my questions and quiries ; many thank to all who responded to my Q & Q
 
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