A four-cylinder powerhead has bumped the 90hp Mercury FourStroke Big Foot outboard motor ahead of its three-cylinder Honda and Suzuki competitors.
Four cylinders are better than three with the 60hp Mercury Big Foot outboard motor.
Originally published in TrailerBoat #265, January / February 2011.
Among boat engine manufacturers there's been a trend back to deep gear ratio outboards that convert engine torque to thrust at the prop far more efficiently than smaller-ratio gearcases — and the FourStroke 60 Big Foot is one of these.
Whereas the standard-ratio Mercury FourStroke 60 has a 1.83:1 gear ratio, which is fine for lighter tinnies to 4.5m, the Big Foot model has a 2.33:1 ratio and can handle tinnies to 5.5m. It also fills the gap between the standard Mercury FourStroke 60 and the 75hp Mercury 75, which although having the same 2.33:1 ratio, is really a de-rated 115 and 53 percent heavier.
The 60hp Mercury four stroke Big Foot has the same powerhead as its 50hp Mercury 50 counterpart and uses the same pistons and conrods from this engine and the F40. The simple SOHC powerhead is a non-interference type where the valves won't contact the piston crowns should the camshaft belt break. Because of the SOHC design, valve clearance adjustment is also easier than some DOHC engines in this power range.
Like all four-stroke EFI Mercury outboards, the 60hp Mercury Big Foot can be fitted with SmartCraft instrumentation that displays functions like fuelflow and range-to-empty. It also includes a paddlewheel-operated speedometer. SmartCraft is very easy to use compared to the systems offered by some other outboard manufacturers.
The under-flywheel alternator has a higher output than some of the direct competition but the engine management computer uses 5amp. The fuel-injectors are an automotive type with injection pressures of only around 42psi or 2.9bar, so the entire fuel-injection system is understressed.
In my opinion one of the most important features of the Mercury FourStroke 60 Big Foot is its four-cylinder powerhead, instead of the three cylinders now favoured by Honda and Suzuki for their four-stroke 60s. There's simply no comparison between three and four cylinders, and the lack of vibration across the entire rpm range makes the 60hp Bigfoot a much more pleasant engine to use on a daily basis.
The review Mercury 60 Big Foot was fitted to a Stacer 529 Northern Fisher CC to showcase its ability to power larger tinnies. Spinning a 14in pitch Quicksilver alloy prop it did a better job than expected but — and this was also to be expected — holeshot acceleration wasn't spectacular.
Even so, seeing as its weight was 35 per cent less than an F75, it did help fore and aft hull trim, enabling the 529 to plane at a remarkably low speed. And once planing, acceleration out to maximum speed was quite good.
The FourStroke 60 started instantly hot or cold and didn't blow any oil smoke, nor was there an oil smell when backing upwind. Power astern was good, provided the antiventilation plate was kept at least three-quarters immersed, but as expected the Mercury control box was notchy in its operation.
Access to the powerhead is very good with the engine oil dipstick, canister oil filter and fuel filter easily reached. The recommended servicing intervals are every 100 hours or annually (also for waterpump impeller replacement) after the first 20 hours or three months. There's no special service required for replacing the camshaft timing belt, which is designed to last about 1000 hours.
The four stroke Mercury 60 hp Big Foot price is $9165 RRP. The recreational-usage warranty for the F60 FourStroke Big Foot is five years providing it is maintained at an authorised Mercury Service Centre.
Through full-lock figure-of-eight turns no prop ventilation occurred and, surprisingly for an alloy prop, there was no prop blowout when the engine was at the limit of its trim range at WOT.
Originally published in TrailerBoat #265, January / February 2011. Why not subscribe today?