HELP!!! 1968 100hp evinrude

hello guys! i need some help today with the charging system on a 1968 evinrude 100hp motor. by the way i have ordered the book on this motor but have not recieved it yet so i could use all the help i can get at this point in time. just need to know if a boat motor charging system is the same as the charging system in a car the reason i'm asking is because on a car motor if you disconnect the pos battery terminal the car should stay running and if it stalls then the altanator is bad. is this the same with my boat motor also? because the boat motor will stall when disconnecting the pos terminal and if it should not stall when the pos terminal is removed what do i need to repair to fix this problem?<br /><br />thanks Roger