Small Outboard Update: Battery-less EFI

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efi outboard

Some outboards all the way down to 15 or 9.9 horsepower now have EFI, thanks to battery-less EFI systems.

Last week we told you all about the new Yamaha F25 outboard, which has battery-less EFI. But this system is important enough, and is showing up on so many new portable outboards, that it deserves further discussion.  Just what is battery-less EFI, and why should you care?

efi outboard

Some outboards all the way down to 15 or 9.9 horsepower now have EFI, thanks to battery-less EFI systems.

We all know that EFI is a more efficient system than a carburetor. And larger outboards have been running with EFI for many years. It’s always been a problem for small outboards, though, because EFI requires electricity. And if you had a small, portable outboard on the transom of a skiff which you started manually, EFI wasn’t an option. These newer battery-less EFI systems are exactly what they sound like: EFI with no battery. Manufacturers have accomplished this by harnessing the energy you create as you pull on the starter cord, to generate a charge that brings the EFI system to life in miliseconds.

Some manufacturers claim that their system does this on the initial tug, leading to reliable one-pull starting. Others say the first tug electrifies the system, and the second tug starts the engine. We’ve now run a number of engines and our feeling is that regardless of the manufacturer’s claims, these engines virtually always start on either the first or second pull. But stating that any of them always start on the first pull is a bit of a stretch; how hard and fast you pull the cord does seem to have a significant impact on the results.

Aside from the usual benefits of EFI on any engine (improved efficiency, more reliable starting, and smoother running), outboards gain some extra advantages. First off, on all of these that we’ve run, including two tests that have included substantial use lasting for over a year, it’s never taken a third pull to get the engine running. They really are that reliable on start-up. Secondly, ethanol issues that normally plague small, carbureted engines are completely eliminated. I personally live in an area where non-ethanol gas isn’t easily available, and this has been a huge relief. Since the system is always pressurized and contained the fuel isn’t exposed to the air, and there’s no carb to get gummed up and clogged. Finally, all of these engines have run smoothly and reliably from start to finish. There are no jets or set-screws to adjust, no float bowls to deal with, and no pieces or parts that need regular carburetor-style attention. And you can enjoy all these EFI advantages without having a 50-pound battery in the back of the boat.

If I were looking at a new small, portable outboard in the 15 to 40 horsepower range today, would I go out of my way to make sure it was a battery-less EFI model? The answer is yes—in fact, I recently picked up a new 25-horse outboard for my 16-footer and didn’t even consider one of the less expensive, older-tech models. These new battery-less EFI motors are that much better, period.


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