Fuel Burn Rate

[whiteman]

I'm checking out fishing destinations up to 100km from the boat ramp so I'm starting to look seriously at the range of my boat (if you're interested, it's a 5.3m Quinnie with 115 2-stroke Yammie - 160l tank). Of course I can't trust the fuel gauge and I'm not sure the tank is full even when fuel spills onto the petrol station driveway!

In fact, I have no idea how far I can go on, say, 50l of fuel. A couple of questions then:

- are any of you confident you can reasonably judge your fuel burn rate over different conditions (WOT vs trolling, smooth vs rough) and if so, what did you do to get that feeling of security?
- are fuel flow meters OK? I have a Navman 450 which can have one attached, but are there better options?

[Barrymundi]

On my 115 Yammie I worked on 1 litre = 1 kilometre for good conditions

2 litres = 1 kilometre for rough conditions.

The navman fuel monitors are good once you calibrate them. They can be a little bit of a pain setting up.

If Vicky paddles you can do the 100ks on very little fuel ;D

[Lucky_Phill]

Allowing that rate is fair, Alan, but in reality Whiteman should do better.

The trouble with 2 strokes is that they use fuel idiling or wot.

At idle they tend to just chuck it out the exhaust.

I would stick to the rule of using 1ltr per kilometer. And should you get to your destination and back and have lotsa fuel in the tank, be thankful.

It is easier to take trips with a full tank, set your GPS trip meter to zero every time, and fill up after the trip. You'll soon get a good working knowledge of the fuel usage.

and 3750rpm is a very good range to sit on whilst travelling.

Cheers Phill

[bungie]

I have an old 150hp 2 stroke, pushing a 17ft fiberglass runabout around the bay 28 - 30 knots I get about 1 nautical mile to the litre.

[mackmauler]

No wonder the price of fuel keeps going up, at the rate you 2 stroke users go through it a worldwide shortage is inevitable ;)

(happy honda owner) ;D

[krazyfisher]

the reason fuel keeps going up is you 4 stroke owners dont use enough. atleast we buy in bulk.
and I get 1L per 2km in the bad stuff with a 70hp 2/s dont care what I get on a good day

[craigie]

It seams like 1-2 km per litre is a fair gestimate.
I've got a 115 Opti Merc waiting to be fitted to a 5.4m F/Glass that I have done some calculations for. For the 40+km round trip from Scarborough to Tangalooma and back, I should use about 25 - 30 litres of unleaded fuel. Will confirm these figures in Feb 2004 ;D ;D.

Cheers Craig.

[Big_Kev]

You are correct there Rob for sure.
The way these two strokers keep pumping out the pollution all the fish will be dead and we won't have to go fishing after all.
And the air will be filled with smoke and we won't be able to see where we are going anyhow.
Any arguements refer to Rob Mackmauler. LOL
Cheers Kev

[Kerry]

Feeling of security comes from knowing ones boat, back to front. That takes time to get enough data to feel confident (that's not necessarily secure) in how ones boat performs in different conditions.

On a good day around the 1Nm to the litre, but depends on what type of "operator" you are, as what generally chews fuel with an outboard is constantly up & down on the throttle. Other days expect to use more, sometimes much more.

A log/diary of fuel v distance travelled will give you "your" answers. #

Anyway 100km in a single engine 5.3 quinnie is really exceeding the feeling of security.

"better options" #;D yeah use a stick, cheaper and always works #:-X.

Cheers, Kerry.

[Greggo]

Try this for size. Last weekend,Jacobs well down to goldcoast seaway, back to the jumpinpin bar, up to sliping sands and back to Jacobs Well with a bit of stuffing around in between. 115 Optimax on a 18ft half cab Mustang. My Smartcraft gauges [which i have proved to be very accurate] told me i had travelled 57.4 klm on 23.9 litres of fuel. Any fourstrokers out there with a similiar rig would be interested to here your figures.

[Cloud_9]

i have 90 hp merc 2003 model on 4.8m glass C/C.
2_2.2Km per litre average, i did the flathead classic in the 3 days i used 65L i have 75L under floor.
those navman things are very good i here not hard to set up like somepeople think.
fill your tank/ tell the unit howmutch fuels in ther tank thats it not hard at all.
i think u just reset it every time u fill up. just like trip meter.

[adrian]

i run from manly to the tanaga wrecks a return trip of 80kms .the fuel use is 40 when flat and 56 when round .but i've only got a 40 2 stroke evenruide on the back of my quinnie. so i use a guess of 2km/ltr if in any doubt carry as i do spare fuel tank of 23 ltrs that much will get me home from anywhere in the bay
also i ran the tank dry while in the river when i first got it so that i know what the gauge say when bone dry . lucky i did asit showed 1/4 of a tank of fuel when it died
anzac

[whiteman]

Thanks for the responses. My comments from what you say is:

- Vicki doesn't paddle and we only have one of these completely useless (but legal) things on board;
- I don't usually fill up at a garage, rather from cans so I don't often carry 100% of fuel, this makes keeping logs difficult;
- I thought carrying cans of fuel on board was one of the big boatie no, no's
- I usually sit on 4k revs unless the kids want a p... or we see surface fish and break out the Halcos;
- I don't care if 4s's are the best things since braid, I paid a heap for my 2s and I'm very happy with it;
- I need to get friendly with the resident population on Palm Island so I have a half-way point (yeah right!)

[team_mongo]

whiteman,

Have a 5.6 quinnie with 115 merc 4s,
Avg 1.5 nm/l= 2.7km/l at about 38 on the tacho/navman @ 22 knts on the flat.
In rough stuff about .8 nm/l.

I've found my navman fuel computer overreads, but I have yet to calibrate it. They say once you calibrate it, its pretty accurate. Have to do that one day....


George

[Big_Kev]

Well mate you asked the question.

[Cloud_9]

Just filled up Cloud 9 after the big mackeral chase from couple weeks ago, had reel hard on board for the day guessing distance about 90 to 100 km used 45 litres.
Kev any idea how far we traveled chasing the macks when u came out???
we left scarborough to briby across to m1 then up to mw12 then back down to m1 to tangalooma then back to scarborough. like i said guessing distance gee i miss my GPS [smiley=bigcry.gif] [smiley=bigcry.gif] [smiley=bigcry.gif] [smiley=bigcry.gif] [smiley=bigcry.gif]

[Greggo]

George
Your figures sound very close to the mark. Cheap day out on the water mate. As far as fuel economy goes the optimax is right on your tail. "Go the Mercs"
regards Greggo.

[Big_Kev]

I would have thought about 80 to 90 Jamie.
But you give it some for a fair bit as well.
Cheers Kev.

[opimax]

giday i run a 135 optimax on a 575 f/g on aveage i work on 1 ltr per km. with 160 under floor thats a good range. seems to be the norm lee

[jethro6641]

::) ::) ::)Mate I 'm running a 225 Optimax on a 6.5m Signature and I always work on the average of 20 litres per hour. No matter what the conditions this always seems to be on the mark. Average trip in average conditions is around 115 kilometers round trip and I use about 70 litres of fuel.

Cheers,

Jethro