Today's spark plug tip - what does this mean?
When you take out your spark plugs, if the colour of the electrode is metallic grey, and the electrodes are grainy or stuck fast, the causes may be: The ignition is too early because the insulation is too hot – you may have the wrong spark plugs. If this is the case the power will decrease sharply. Get the engine checked in a workshop before you use it again.
(Taken from the Skipper’s Outboard Motor Guide, a brand-new fantastic waterproof handbook by Hans Donat, published by Adlard Coles Nautical, ISBN 978-1-4081-1418-6 – £10.99, and available from all good nautical bookshops)