Mariner outboard - what fuel consumption?

ProDave

ProDave

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I have a mariner 4HP 2 stroke outboard to power my Frolic 18 sailiing cruiser.

My question is how long should I expect the motor to run on a tank of fuel? It only has it's inbuilt fuel tank which holds no more than half a gallon.

Also doe anyone have a link to the owners manual or service manual for this engine?
 
general rule for a carb 2s is 1 gallon per 10hp per hour flat out - much as Davy S has put it in metric terms!

so your 4HP will do (at least) 33minutes on a litre - and at half throttle it will well over an hour.

All your responses therefore fit to some degree - it's about how you use it.

I have the same engine, but have converted it to use the 10l external tank that I ended up with when some t'leaves borrowed my 4HP 4 stroke....

I will have a manual somewhere down at the boat but it doesn't contain much useful info - and certainly nothing on fuel consumption! Mines now 10 years old so suppose I ought to see if there's any maintenance due.... :)

Just had a quick look online and the tank seems to be rated at 2.4l capacity on that engine (2.6 US Q)
 
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You should able to down load acopy of the owners manual from THE DOWN LOAD CENTER AT BRUNSWICK MARINE

You will first probably need to look up the year in the model year identification pages on the same site.

It not always easy to find the right one .. you may be lucky first time or it may take a bit of hunting.

Difficult to say on the fuel consumption. Try it at the sort of cruising speed you will normally travel. Could be several litres per hour at WOT but a lot less at a gentle cruising pace .

FWIW I have a 6.6 US gallon /25 litre tank for my 6 hp 'Rude and if I am going far I take extra in cans. With hindsight I would recommend 2 smaller tanks although the capital outlay is higher.

I would not consider an outboard with only a small integral tank other than for pottering around in sheltered waters.
 
Thanks for all the replies, very helpfull, and thanks for that link I now have the manual.

Mostly the motor is just to get us in and out of port, or when the wind is wrong. But my main reason for asking is next year we have plans of taking her through the Caledonian Canal, which involves at least 20 miles motoring each way, so we may need to carry several gallons of fuel with us. Hopefully before we do that we will have more experience of actual fuel consumption.
 
I agree with the poster who says an internal tank is not really up to the job.

It's not easy to keep topping up a tiny tank in lumpy seas, if it's on a transom bracket it could be downright dangerous to the person leaning over the stern

There's also the consideration of spilling fuel on a hot engine, and I would want to stop the engine while topping up, for fear of sparks; stopping may not always be possible in heavy conditions at close quarters...

In case you don't have one, a 'splash-proof' funnel witha curled lip is essential, does help a lot.

I have a Mariner 5 2-stroke, and used to have a Yamaha 4.

With an easily driven 22 footer I get a genuine 2 - 2.5 hours per gallon in normal conditions, would only expect less if for some reason really struggling to motor into heavy weather.
 
conversion of that model to use an external tank (as an option) was pretty easy, the fuel connector bolts on to existing holes, bit of pipe to a tee etc - then mercury/mariner 12l tank with fittings (used to come as standard with 5 upwards and 4/4s etc) , or 22 or 30....

total new parts about £45 inc postage - but you may get a tank set up S/H for less. Loads via ebay.

nice size for what you are indicating, and you then have the integral tank as your 'emergency' ie you can run the external empty each time.
 
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