I recently bought this original Merc Monterey with 30K miles. Got it running pretty well but it still is a little rough. Changed the ignition to solid state and put in new plugs but still have trouble starting sometimes. Still 6V system and am reluctant to change to 12V for a number of reasons, mostly having to do with compatibility of lights, gages, accessories, etc. Put in an auxiliary, switched electric fuel pump to prime the system but still have problems starting. Have not touched the original carburetor. Have been using 87 octane gas with 10% ethanol. Could this be causing a problem? If you have had any experience along these lines and have suggestions for a remedy I would be most appreciative.Thanks. /rt