Reply With QuoteThe Suzuki 250 on the 680 haines would use 10-12lt an hour at 7 knots.
The 150 on the poly chews the juice at 8knots - the little boat is just off plaining at that speed. If I slow down to 6 knots it uses about 5-6 litres an hour.
Cheers
yamaha 225hp four stroke at 2400rpm and 7.5knots it consumes 18ltrs per hr as i found out last weekend trolling for three days and used 570ltrs with a bit of high speed motoring out and back in.
cheers jim
The Suzuki 250 on the 680 haines would use 10-12lt an hour at 7 knots.
The 150 on the poly chews the juice at 8knots - the little boat is just off plaining at that speed. If I slow down to 6 knots it uses about 5-6 litres an hour.
Cheers
Last edited by Luke G; 18-12-2008 at 09:00 PM.
Originally Posted by siegfried
Was sitting on the bare minimum. around 7-8 knots im guessing, as for being under proped im running a 15, the boat has had a 17 on it but its only good for longish trips.. works hard to plane..... last trip out i dident use quiet that much... although shes always guzzled from new, id like to stick a 4 strk on the boat but its hull decal says " maximum 156kg including fuel and motor"
if i was to go 4 strk it be on the maximum without fuel...
i thought of a 60hp big foot 4 strk but unsure if id be under powered....
Some figures off the F&B site for a single evenrude 70hp 2 stroke. Each motor hull will be different but this gives an idea of how bad the rev range around 2000 3000 is on fuel economy. Note the range does not start to fall off again until 5000 rpm. Sorry I cant seem to get them to post the same as I edit. The last figure is range ie 2500 rpm Range 75 kl
R/Min L/ph G/PH N.Mpg Knots Kms Range
1,000 2.52 0.55 2.81 3.1 5.7 140
1,500 3.90 0.85 2.52 4.3 7.9 125
2,000 5.70 1.24 2.29 5.7 10.5 114
2,500 9.00 1.97 1.52 6.0 11.1 75
3,000 10.80 2.36 4.53 10.7 19.8 113
3,500 13.20 2.89 2.99 17.3 32.0 149
4,000 15.00 3.28 3.20 21.0 38.9 160
4,500 16.80 3.67 3.25 23.9 44.2 162
5,000 19.80 4.33 3.15 27.3 50.5 157
5,500 26.40 5.78 2.55 29.5 54.6 127
5,750 30.60 6.70 2.32 31.2 57.8 116
.
Mate fill it up and troll only for15 min it will give you a reasonable indication.If you sqirt out to the grounds thus chewing abit of juice it may look worse. I had 98 johnno 70 pushing 5.2m tinny that used nearly twice the fuel of my 140 jonno/zuki pushing a 5.6 grp hull. From memory 6.5 kts in that boat was @ 2500 rpm. Imsurprised that you need to give it 3000 to do 6-8kts...I wouldnt be too worried about that decals recommendations ,a 60-75 4 banger and that boat would be cool, I know max hp is nice but unless you have to run a bad bar(I do) every day or pull skiers etc youll be right. Let us know how you get on. Good luck
not sure that the 60 would push it along enough to satisfy me, as the 70 is a bare minimum i find.. still takes too long to plane in my books... or it could be im just impatient..... boat is definatly arse heavy too, i usally stick another 80 liters up the front just to compensate it a bit...
looking around iv come up with the figure its pushing 700kgs, without people or gear... possibily why so much power is used to get a good trolling speed?
got any pics of the rig?
might help some, to help you
Sorry Ice I thought it was a Stacer- (TIN) I would be looking for 90(min) to 115 for that boat, I have no doubt that with gear and ccrew you most likely underpowerd to buggery and the motor would be working hard through the entire rev range. They have a bit (? 17-19 deg deadrise) and dont slide over the water like a flatar$e tinny. I am guessing it is afactory rigged show and they have a habit of mismatching motors eg: 560 barcrusher 115 2stk yammy=sh&^%$SE-same boat with 140 zuki 4= horn. Unfortunately (although I hope Im wrong) your boat is going to be a bit thirsty at those revs.Good luck mate and let us know how you get on.
Ice - do you get a WOT of 6000 rpm? The WOT range for your 98 Johno 70hp is 5000-6000 but you should be looking to get at least 6000 rpm. How high is your motor on the transom & do you have a foil fitted? Any pics of the motor trimmed in?
cheers, HR
mate ill post some pics of it trimmed in.. plenty of angle of attack tho,
no foil that is next...... with trim i could take it to 6500 if need be. only run it to 5500 max tho. usally cruise on about 4100 4200,
i see the same boat as mine mine in ebay its got a 60 merc 4 strk big foot fitted... going to email the person and ask them on performance specs..
25 Bertram runabout, 5.7 Volvo Duoprop 280hp
At troll of 7knots I use approx 12lts/hr.
At cruise of 22knots I use about 35lts/hr approx.
Noosacat 3100
Ice, 6500 rpm WOT, that's huge for a motor with a recommended max WOT of 6000 rpm. I've got a 1998 70 Johno too, so hence my interest. It's on a 17ft tinny & with 2 blokes & gear, fuel etc it's pushing about 900 kg. It's spinning a standard OMC 13.25 x 17P 3 blade.
Looks like the poor fuel consumption in 2000-3000 rev range for the 70 Johno is a fact of life for that motor. Something I was unaware of until this thread. But I wonder how yours would go with the motor raised as high as you can get it with the 17P back on?
cheers, HR
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