Greg Copp takes a close look the Yamaha F25G which is compact but packs plenty of a punch…
It is long overdue – a 25hp engine on a par with the lightweight 2-strokes of old. To be fair, Yamaha’s F25G, in short-shaft tiller form, weighs 57kg – 7kg more than their old 25hp 2-stroke motor, but you would not know it to look at it. This twin-cylinder 432cc engine is compact and just about light enough for two to manhandle onto the transom. Unlike its bulky competitors, it actually appears compact enough to be a 25hp 2-stroke engine, and does not look oversized on a small boat.
More importantly, it is a great performer. It packs plenty of punch low down, taking off like a 2-stroke, just without the noise and the smoke. After I had completed an initial three hours of running in, I started giving it bouts of wide-open throttle. At full bore, we were hitting 24 knots, two up, plus a big dog. Some years back I had a 4.3m Quicksilver 430 inflatable with a 2-stroke 25hp Yamaha that managed a fraction less, so I can’t fault it on top-end power. Once it has done another 10 hours and loosened up, it is likely to be a touch quicker.
Cruising at 12 to 15 knots in my 4.5m Wetline inflatable, the motor felt relaxed, and it also proved very frugal. Over a five-hour period I used half of a 5-gallon tank. I did have to check it twice to be sure, as I expected to be running on vapours by this point. During this five-hour period, I had spent the initial hour at 5–6 knots to bed the motor in, and then spent three hours mainly at an 8-knot semi-displacement speed before running at planing speeds of between 12 and 20 knots for over an hour. To quantify what the engine was driving, the boat weighs 119kg, the crew weighed 160kg, my dog 40kg and the fuel/kit 60kg.
One thing I do not like about tiller-steered boats is the awkward engine ergonomics. With the F25G this is massively reduced with a series of simple but effective features. For starters, the gear change is where you can easily use it, just behind the twist-grip throttle, and selection is silky smooth. The tiller is not too short, as they often can be, so no aching arm syndrome from reaching back. To make life even easier, you can have power trim on the tiller, with the button located where your thumb rests. I was keen to test an engine with power trim, but this involved having to bolt the engine to the transom rather than traditional thumb screw clamps. Due to time restraints I had to shelve this option, but the concept is perfect for shallow waters.
However, I did have the optional electric start, which I initially thought was an unnecessary luxury – but I was proven wrong. Faced with getting off a beach with a strong wind driving the boat back onto the sand, I had a slight dilemma. After getting Jackie and my dog Max on board, I had to push the boat out until the water was up to my waist. Then I had to pull myself over the tubes, release the engine from the locked raised position, start it, engage gear and quickly back out before the weather had me back on the beach. If I had not been able to fire the engine up instantly at the press of a button, I do not think I would have managed it on time. Having an electric start also gives you a charging loop to keep your battery topped up, so you can run navigation lights, and in my case a 5″ Garmin 276Cx chartplotter – a handy tool when working close inshore.
With the engine security transom clamp in place, you need to get familiar with the release catch for the manual engine tilt/trim. Like any manual-trim outboard engine, you can pull it up into the fully raised position when beaching, or into the shallow-water position at half-mast when running into very shallow water. Pulling the motor up into either setting is not a problem, but releasing it can be a bit awkward if you are not familiar with it. I made a point of practising the release catch before I cast off from Mylor. The F25G is also fitted with a very effective steering friction adjustment system, which on a tiller-steered engine of this size is a must. Pottering around the marina you want it on a zero setting, but the moment you get out onto open water you need to turn it up. This is easily done using the stainless steel lever under the powerhead. Being able to quickly fine-tune this is a must, as the torque reaction of an unfettered tiller-steered 25hp outboard can prove dangerous.
The F25G enjoys battery-less electronic fuel injection (EFI), has variable trolling speed (VTS) controllable on the tiller, and a high-output alternator that is essential for long periods at low speed. It can be stored on its back or laid on its left-hand side – for either position it has resting pads. You can have Yamaha’s Y-COP engine immobiliser and interface the engine to digital gauges if need be. The heavy-duty top cowling with an effective chunky rubber release catch that actually works as it should is typical of the high standard of finish and engineering that is evident throughout the engine. On the left side of the engine, the oil filter, oil filler, ignition coil and regulator/rectifier are easily accessed. On the right side of the engine, the dipstick can be accessed from within the boat. Its flexible rubber handle locates securely into the powerhead, letting you know when it is either in or out with a reassuring click, so no chance of losing it. An aspect that is particularly handy if you keep the boat afloat much of its life is the cold-flush facility, located on the right side. With the fitting unscrewed you can flush the engine without running it, though it should be said, this is not as effective as running and flushing the engine with muffs.
Once the engine is properly loosened up with some more hours on it, I will run a quantifiable fuel consumption test to see what she burns at a constant planing speed. Weather permitting, this will be in the spring issue.
Further details at: www.yamaha-motor.eu/uk/products/marine-engines/portables/f25.aspx