What amp should your alternater be when running a msd on a single engine application......I ask because my housing on my alternator was cracked and i think it was giving a weak charge to the batteries and in turn not firing my msd properly......If ya have had similar problems post your expierince please..........65amp is what a aftermarket marine alternator is and i dont think that is enough....

65 amp is more than enough for your MSD no worries there. Exact current draw depends on which MSD you are running. Big end Stereo is another story though.