It never ceases to amaze me quite how many things can go wrong unexpectedly when you're on a boat. I was out for a potter on the River Crouch yesterday in my Avon Riblite 3.1m accompanied by RichL who was testing his Yam 2.5m tender and a couple of other friends in their 14' aluminium boat.
My Yamaha 4hp 4-stroke started well enough but ran jerkily right from the word go, which it has never done before. After about 500m it started backfiring and then stopped running altogether, whereupon it spontaneously ignited
After a brief moment of contemplation, which was at least half a second, I realised I had little option but to unscrew the saddle bracket clamps and dump what was a three year old £600 engine in the sea before it caught the sponsons alight or blew up in my face! The insurance claim will be filed tomorrow morning.
Apart from being a particularly unpleasant experience, although inevitably RichL found the whole incident highly amusing and cursed himself for having forgotten his video camera, I would be interested to know if anyone has the faintest idea why it might have caught fire. I've never heard of a similar incident but I'd be surprised if this was a unique occurence.
I've had the engine from new and it's only done about 40hrs. I had it serviced by a Yamaha main dealer last autumn and the carb was cleaned out because a blocked jet was causing petrol to flood out of it. The engine ran perfectly since with no petrol leakage at all. This particular engine model has a well known design fault in that the fuel tank is sited so far from the carb that it takes up to 12 pulls to start it. It also readily leaks sump oil into the top of the cylinder causing problems with hot starting if the engine has been tilted up. Yamaha themselves admit the engine can be troublesome although failed to advise it might blow up in your face on occasion!
In addition, is it likely to be a problem with the insurance company that the engine is lying at the bottom of the River Crouch (it may be possible to retrieve it at LW Springs) or will the testimony of three independent witnesses be sufficient for them to pay out?