How much gas should a 2-cycle suzuki use?

[hercamer]

I have a 97 DT115 EFI suzuki outboard. This is my first bigger outboard and was wondering if anyone had a clue of how much gas these things are suppose to use. I ran on the lake for about and hour to an hour an a half and used about 13 gallons of gas, does this sound high to anyone, if it does, what would you consider normal and what would cause me to use extra gas?

 

[Silvertip]

Re: How much gas should a 2-cycle suzuki use?

A very good rule of thumb for any engine is put a decimal point one position left in the horsepower rating. While not an exact measure of fuel consumption it gets pretty close. Putting a decimal point in the 115 would be 11.5 or 11.5 gallons/hour at wide open throttle. That trick works for virtually every outboard -- two stroke or four stroke, carbed or fuel injected. Ovbiously size of the boat, prop selection, state of engine tune, load and a host of other things affects that but as I said, it gets quite close. So your figure of 13.5 gallons, although a little high, is not out of the ordinary. I have a 75 HP Merc on a walleye boat. I run a fuel flow monitor at wide open throttle -- two aboard, full live well and fuel tank it burns exactly 7.5 gallons/hour at WOT.

 

[freddyray21]

Re: How much gas should a 2-cycle suzuki use?

135 hp Johnson back in the 70's we used to figure 6 gallons an hour pulling skiers. Sounds awful low compared to the above figures, but we never ran full throttle.

 

[Silvertip]

Re: How much gas should a 2-cycle suzuki use?

This technique is for WOT only. Obviously any engine will burn less fuel at settings less than full trottle. The example I gave with the 75 HP Merc which burns 7.5 g/hr at WOT burns only 4.8 at 4200 RPM.

 

[freddyray21]

Re: How much gas should a 2-cycle suzuki use?

true but I don't know many boaters who run full throttle for an hour and a half. I think a more realistic guess is how much gas will my boat use when I use it like I do.

 

[Silvertip]

Re: How much gas should a 2-cycle suzuki use?

Everyone has their way of telling whether or not they have enough fuel to get where they are going and back. My only pont here is without a fuel flow monitor you cannot begin to figure fuel flow as nobody -- and I mean nobody runs at exactly the same RPM through a full tank of fuel. And even if they did, varying load and water conditions would alter the fuel use. Even a couple hundred RPM up or down makes a rather significant difference in fuel flow. Some folks like to know fuel consumption in miles per gallon rather than gallons per hour. But just like your car, miles per gallon changes dramatically with speed, wind, load, city and highway use. If you know the "maximum" amount of fuel your boat will use in an hour, you can quickly calculate what your range is at WOT. With that info, you are assured that anything less than WOT you have ample reserve. Boat gas gauges are not very accurate and are not even calibrated in gallons so it is of little use in determing cruise fuel consumption.

 

[deejaycee_2000]

Re: How much gas should a 2-cycle suzuki use?

Hercamer ..... Sounds right to me, I have a 115hp suzi on a 19,5 foot baronette cabin cruiser and I finish my tank in about half an hour .... I don't have a built in, only the standard 25 litre (6,6 gallon) tank and that is from stop and go stop and go, ski'ing, wakeboarding etc. Running non stop on a cruise a constant speed at about 3800 rpm my tank will be dry in about 45min max ...... these are just generally heavy on fuel, I can wakeboard with my 140hp yamaha on a speedboat for at least an hour to an hour and a half on a standard tank of fuel ........

 

[hercamer]

Re: How much gas should a 2-cycle suzuki use?

I never knew they sucked the fuel like that! These trips to the lake every weekend get expensive quick!

 

[OptsyEagle]

Re: How much gas should a 2-cycle suzuki use?

Keep in mind that running a boat is like driving up hill all day long. That is why they do not put more gears on these engines because you will never need to move her out of first gear. The drag on these things is intense and to prove it, just kill your engine immediately after WOT and see how quickly your boat comes to a stop. The next test of how much work your engine is doing is those unfortuneate times that one has to pull out the old oars and row home manually. I'm usually soar for a least a week after a couple hundred yards of that.

 

[Silvertip]

Re: How much gas should a 2-cycle suzuki use?

If you are still skeptical, go to Yamaha's web site and click on Peformance Tests. You can select any engine (2-stroke or 4-stroke), and virtually any type of boat combination they have tested. They list fuel consumption from idle all the way to WOT. They show prop types, weights, speeds vs RPM and other data. Most importantly they show fuel flow rates. WOT fuel flow is nearly the same for either 2- or 4-stroke. 4-strokes have the advantage at anything less than full throttle. Just make sure you compare the engines on the same boat.