Maintenance and usage tips for the British Seagull engine
Lubrication of the gearbox of a British Seagull Outboard Motor. You must not use grease. Oil only must be used. Any good quality gear oil will do, of approximately S.A.E. 140 viscosity. From 1978/1979 models, EP 90 was recommended. Fill up to filler plug hole measured with engine in upright position.
The sparking plug. Nearly 90% of engine failure is due to plug trouble, and yet, plug trouble is almost entirely avoidable. Use the right plug "Champion D16" or equivalent. Points gap 0.020 in. (0,5 mm). For later models with breakerless ignition 0.035 in (0,9 mm), not less. Always carry a spare, good, plug…not just another plug which has probably been rejected faulty on some previous occasion!
If the engine cuts out suddenly or do not start after tree or four pulls it is ten chances to one that it is plug trouble. Whip out the plug at once and check.
The boat and speed. Now as regards obtaining maximum speed from the whole outfit:
First of all, in any displacement dinghy, that is to say one which goes through the water, as opposed to a speed dinghy which planes on top of it, maximum possible speed of the boat is governed entirely by the length of the boat and not by the power exerted by the engine. To some this may be surprising but it is a fact. As a rough guide, a 9-foot hull will reach 4.5 knots and a 16-footer 6 knots; other lengths in proportion. Always remember, however, that it is a waste of effort to try and drive a boat above its calculated maximum referred to above.