Grover

Magnet test is a great idea. A simple, non-destructive solution. I'll check it out.

That's what I need to establish. It appears to be metal, but BSS aren't convinced. It's sold as compliant for marinised engines.

I'm told that this filter, which is sold by chandlers for canal boat use, may not be BSS compliant, as it doesn't appear to be of metal construction. Has anyone had this problem, or had to replace the filter with a more obvious metal canister?

Thanks for this suggestion. I'll check this out too.

Thanks Tony, I'll have a look at the spacing options.

its a pre-owned boat and judging by the number of spare and used belts in the locker, this has been an on-going problem. Does anyone know a source of pulleys as I'm hoping to find one of appropriate dimensions that will avoid the need for spacers?

The alternator appears to be fitted properly and the alternator pulley is shimmed to ensure that the belt clears the end of the engine block. I wonder whether a replacement crank pulley has been fitted with insufficient stand-off from the front of the engine.

Just completed a short shakedown cruise with a new boat fitted with an Isuzu 42 engine and shredded the auxiliary alternator belt. On closer inspection the alternator pulley is about 6mm out of line with the crank pulley when viewed from above, which looks like about 10 degree side deflection. I can't believe that it's always been misaligned so it looks as though a spacer is missing between the two drive pulleys on the crank. Does anyone know whether this is likely or have a fix for this?