OMC Evinrude 5

When OMC's Evinrude and Johnson twin cylinder two-stroke 5 and Suzuki's twin cylinder 5 (de-rated from the 8) were dropped mid-'98 in favour of the Suzuki-built single-cylinder 5, OMC and Suzuki were left without a 5 suitable for trailerable tinnies to 3.7m.

But for these hulls, the company now has a single-cylinder four-stroke Evinrude 5 that also complies with US EPA 2006 regs.

Unlike its direct Honda and Tohatsu competition, the Evinrude has a belt-driven camshaft and electronic reduction of revs down to 2000 by the CD unit if the oil pressure drops below safe levels. There's also a renewable oil filter and even a separate dipstick in addition to the oil filler cap for access to the sump.

Cleverly, OMC has retained the lower unit from the twin cylinder 5 and existing two-stroke 6/8 model, which has the shearpin aft of the prop for easy prop swapping.

Overall, the Evinrude motor appears more robust than its Honda and Tohatsu competition and potentially should stand up better to the rigours of long-term use (abuse).

The new powerplants feature a fold-down carry handle in the transom bracket but no lower cowl lugs to indicate that the motor must be laid down only on its portside.

The well-rounded upper and lower cowls with no protrusions ensure there's nothing to snag a fishing line on when casting. There's an adjustable idle speed knob on the tiller handle and the upfront gearshift makes low-speed handling very easy compared to direct opposition fives.

Maintaining the Evinrude is not as easy as its Honda or Tohatsu counterparts, however, and cleaning the oil filter is a finicky job At least oil changing is simple with a slot-head drain screw in the starboard side of the leg.

The Evinrude was too heavy to be tested on my 3.0m deHavilland John 10 punt, preventing me from directly testing it against its Honda and Tohatsu counterparts. Instead, I used it on my 3.6m Sea Al Super Skua tinnie, which displaced 255kg.

After some frustrating trials I found a cold-starting system that worked. The primer bulb was squeezed and the choke pulled out, followed by cranking over the motor twice. The choke was pushed in and the motor cranked twice more before it would start. When idling, the Evinrude ran like a single-cylinder diesel, visibly shaking the Super Skua at the bow.

Spinning the standard prop, the Evinrude trolled at a low 4.04kmh at an estimated 1200 revs, consuming 0.20lt/hr. This was about 50% less than a single-cylinder two-stroke Merc 5 under identical conditions.

The strong flow pilot water discharge was visible and even on the shallow water drive setting, power astern was good. Providing the anti-ventilation plate was kept immersed, no cooling water starvation occurred and the thermostat maintained constant temperatures during extended Dead Slow Troll (DST) operation. Unlike the Tohatsu 5, the carbie didn't suffer vapour lock.

At WOT, the Evinrude registered 16.73kmh on an estimated 4500revs consuming 2.12lt/hr this compared to 20.89kmh for the twin-cylinder 5 spinning the same prop and 19.44kmh for the Merc. As these consumed 3.99 and 3.03lt/hr respectively, the Evinrude returned significantly better (52 and 23%) fuel efficiency.

Interestingly, vibration and noise levels from one third throttle upwards were low for a single-cylinder 5, and at WOT, less than any other single-cylinder 5.

Service intervals are every 100 operating hours or once a year after the first 20 hours or three months, when the valves must also be adjusted. The crankcase oil should be changed every 50 hours or six months while the filter can be cleaned every second oil change The waterpump impeller should be replaced every 100 hours.

Based on my experience of previous OMC products, the four-stroke Evinrude 5 should stand up well to saltwater usage.