torquing
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WITH ANDREW NORTONCooking with gas
TOHATSU’S FIRST LPG OUTBOARD MAKES PETROL SEEM OBSOLETE...
T
ohatsu
Corporation is
nothing if not
innovative. It
developed the
world’s first battery-less EFI
for four-stroke outboards
and now has introduced
its first small dedicated
LPG outboard that runs on
separate gas bottle.
According to Tohatsu,
using propane or LPG
reduces Hydrocarbon and
Oxides of Nitrogen (Nox)
emissions by 30 per cent,
Carbon Monoxide by 56 per
cent and Carbon Dioxide
by 15 per cent over a
comparable output four-
stroke petrol outboard.
Oxides of Nitrogen help
create acid rain, carbon
monoxide kills humans
and carbon dioxide is
a greenhouse gas that
contributes to globalwarming.
But using LPG in an
outboard does way more
than just reducing these
nasties. It makes a small
outboard run smoother
because there’s no transition
from idle to main carbie jets.
And of course per litre LPG
is way cheaper than petrol,
even though the engine
consumes up to 15 per cent
more fuel than a comparable
output petrol engine.
The Japanese-made
MFS5C LPG utilises the
same base power head as its
petrol MFS6CS counterpart,
which develops 5.9 brake
horsepower at 5500rpm.
Switching to LPG means
the engine loses 0.9 BHP at
the same revs but testing
the engine under identical
test conditions shows the 5
develops the same bottom
end torque as the 6 but losessea trials
Single MFS5C LPG on flat-bottomed Sea Jay 3.4 Punt, total
290kg including two adults and fishing tackle. Average of
two-way runs on Lake Macquarie NSW, beam seas to
20cm.
8 INCH PROP 7 INCH PROP
TROLLING
RPM 1200 1300
KTS 2.1 2.0
DB AT 3 METRES 59.0 59.2
FAST IDLE
RPM 2000 2000
KTS 4.0 3.5
DB AT 3 METRES 66 66
MINIMUM PLANE
RPM 5200 5800
KTS 12.6 12.6
DB AT 3 METRES 83.5 86.2
WOT
RPM 5300 6200
KTS 13.4 14.7
DB AT 3 METRES 84 89Swinging the 7 inch prop and averaging 4.0kt including 10%
WOT and 40% trolling operation the engine consumed
0.6L/h. This gives an 88 nautical mile range from the 7.5kg
gas bottle with a 10% reserve.82 tradeaboat.com.au