20 HP Outboard Australia: EFI vs Carburettor, Honestly Compared

A 20 hp outboard is the largest engine most inflatable owners will ever fit, and in Australia you now have a real choice between electronic fuel injection and a traditional carburettor. They are not the same engine with a different badge, and the cheaper one is not automatically the wrong buy.

Here is the honest comparison.

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20 HP EFI vs 20 HP carburettor

	20 HP EFI	20 HP Carburettor
Fuel delivery	Electronic fuel injection, DELPHI ECU	Carburettor
Displacement	356 cc twin	323 cc twin
Dry weight	59.6 kg short / 61 kg long	51.5 kg long shaft
Shaft options	Short 15" or Long 20"	Long 20" only
Start	Electric	Electric
Alarms	Oil pressure and temperature sensors standard	—
Price	A$4,889 short / A$4,956 long	A$4,000 with delivery included
Warranty	5-year (3 + 2)	5-year (3 + 2)

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What EFI actually buys you

Cold starting. EFI meters fuel electronically, so the motor starts the same way on a frosty winter morning as it does in January. No choke routine, no flooding, no standing on the transom pumping a bulb while the tide pushes you off the ramp.

Consistency. Carburettors are sensitive to altitude, temperature and stale fuel. EFI adjusts itself. If your boat sits for a month between trips — which describes most Australian boats — that is the single biggest practical benefit.

Protection. The EFI model carries oil-pressure and temperature alarm sensors as standard. On an outboard that lives in salt water and gets used hard, that warning is cheap insurance.

Fuel economy at part throttle, where you actually spend your day.

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When the carburettor model is the smarter buy

It is 8 to 9.5 kg lighter and roughly A$900 cheaper delivered. If you use the boat regularly (so fuel never goes stale), you are comfortable with a choke, and you want the lightest 20 HP you can get onto an inflatable transom, the carburettor model is a genuinely sensible choice — and it carries the same 5-year warranty.

Be aware it is long shaft only, so it suits deeper transoms and catamaran hulls, not shallow tender transoms.

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What boats take a 20 HP?

• 3.8 m to 4.0 m inflatable catamarans — the natural home for this engine
• Larger monohull inflatables rated to 20 HP
• Boats regularly carrying three to four adults plus gear

Always check the maximum rated horsepower for your hull. Every boat in our range lists it, and exceeding it is never worth the extra knot — it changes how the hull behaves and it voids the rating the boat was certified to.

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Weight is the real constraint

At 51.5 kg to 61 kg, a 20 HP stays on the transom. Plan your setup around that:

• Keep the motor mounted and move the boat on launching wheels
• Use a motor stand at home rather than lifting on and off each trip
• Check your transom height carefully — the extra weight makes a wrong shaft length more punishing

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Tiller or remote?

Both of our 20 HP models are tiller. Tiller steering keeps the weight aft, keeps the boat simple, and suits inflatables where a console would eat the usable floor. If you want a console and remote controls you are into 30 HP territory and a bigger hull.

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Fuel, oil and looking after it

Both engines run straight unleaded with a 12 L external tank included (24 L available). Four-stroke oil changes at the first service and then on schedule keep the warranty intact — the intervals and real costs are in outboard motor servicing in Australia.

If you are pairing a 20 HP with a new boat, look at the 3.8 m and 4.0 m hulls in our inflatable boat range — they are the sizes this engine was built for, and both run a deep transom that keeps the prop buried in chop.