Aordability
versus Environment
ARE FOUR-STROKE OUTBOARDS WORTH
THE EXTRA COST OVER TWO-STROKES?W
ith the banning
of the sale of new
carbie two-stroke
outboards in Oz
next year, is it worth
investing in a new four-stroke outboard
or buying a two-stroke while you can?
After all, outboard manufacturers must
guarantee spares availability for 10
years after the sale of every engine.
So even if you buy a new two-stroke
this year, spares will be available until
2028.
For sheer reliability two-strokes are
very hard to pass up. For example, my
2005 Tohatsu M8B is the most reliable
outboard I've ever had, simply because
there's so little to go wrong compared
to a four-stroke outboard. And its
light weight of only 26kg means I can
lift it from trolley to transom without
breaking my back, whereas a four-
stroke 8 weighs upwards of 37kg. Not
only is this over safe lifting limits for
one person but on my early seventies
3.35m Savage Gull tinny the weight on
the transom would severely damage it,
not to mention the old trailer on which
it sits. This is a common problem with
older hulls that were just not designed
to take the additional weight of a four-
stroke outboard.
In comparison, my 2003 Sea Jay 3.4
Punt is rated to 42kg on the transom,
fine for the hull but not my back. So if
I were to run a four-stroke 8 it would
have to be a bolt-on unit meaning that
when the engine needs a service the
entire boat would have to be towed to
a dealer, way more complex than just
taking the outboard itself.
Another example is the 1988 3.6m
Sea Al Super Skua I owned for 25 years.
Though it was rated to 20hp this meant
two-stroke and not four. The most
powerful engine I tested on this hull
was a Tohatsu M18, which weighed
41kg and drove the hull with two adults
aboard out to a positively scary 27kts.
Yet when I tested a four-stroke Yamaha
F9.9 20 years later this engine weighed
40kg and drove the hull to just over
19kts. No way in the world could the
hull take the 50kg-plus weight of a four-
stroke 20. With both the Tohatsu and
Yamaha engines freeboard at the short-
shaft, transom was very limited and
overall the hull felt unbalanced because
of all the weight aft.
Having said that, engines like the
recently released four-stroke Tohatsu
MFS 20E have closed the weight gap.
And having battery-less EFI it starts
and runs so nicely in comparison to the
two-stroke. Of course, being a four-
stroke maintenance is higher but so is
resale value because most new boaters
are thinking four-stroke, judging by
the total of 69 per cent of all outboards
sold in Oz last year being low-emission
units.
Smaller four-stroke outboards, those
under 10hp, outperform their two-
stroke counterparts because of the
torque generated and the inherently
better engineering. And on the right
hull the four-stroke Aqualine F2.5 and
Mercury F2.5 leave my lighter 1993
two-stroke Johnson 4 for dead while
using less than half the fuel.tradeboats.com.au 29