I too have had to replace split bobbins on the rectifier and exhaust. I have now taken my experience with my sail boat and transposed it to the M3W. For the first four years of ownership I replaced the bilge pump diaphragm three times. Since then I have regularly sprayed the diaphragm with silicon spray. After two years it still looks like new. I now spray the bobbins with silicon every time I wash the M3W. Seven months and over 3,000 miles and the bobbins appear sound. I also spray the tubes running from the engine, but plan to replace those sooner rather than later.
