Outboard SOS

PBO's engine expert, Stu Davies, explains how to troubleshoot outboard motor problems to get them running again

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Whether it be a small outboard to drive our dinghy or a bigger one to drive our fast 'toys', we all have one. But before we look at how to troubleshoot and fix problems, some history wouldn't go amiss.

The first outboard motor was an electric one invented by Gustave Trouvé in 1881, however it was Ole Evinrude who developed the first commercially successful, petrol-powered outboard in 1907. While Trouvé's electric model was a novelty, and American Motors Co produced some gasoline outboards in 1896, it was Evinrude's simple, reliable, and relatively powerful 2-stroke design that revolutionised recreational boating and became the industry standard.

The British Seagull was largely the forerunner outboard for us in the UK. A simple, robust and indestructible bit of kit, it ran on 16:1 (16 parts petrol; 1 part 2-stroke oil) 2-stroke mix that was smoky. Drop it in the sea, and the Seagull would come up for more after a quick swill with fresh water.

There were no fancy electronic ignitions on these engines, just an old-fashioned brass flywheel with magnets embedded in it, robust coils and a set of points to produce a spark. The carburettor was simple, easy to dismantle and clean.

However, the Seagull could be cantankerous, with much winding of bits of rope on the start pulley and pulling to try to start it.

Much like the motorcycle industry, it was overtaken by Japanese/American outboards and their derivatives. They were lighter and more reliable. They were bulletproof; advanced aluminium casting techniques and superior coils and magnets made them so.

Back then, most outboards used a 2-stroke engine power head, driving through a shaft to a gearbox in the bottom half of the 'leg'; simple, powerful and easy to work on. Nowadays, it's a 4-stroke engine with more complexity and weight and the growth of electric outboards.