Well first of all not unless someonw installed an alternator all Olivers with generators are positive ground. When you try to start it how much voltage do you have at the starter? Take your meter and back track and see where your voltage drops are, or let your fingers do the walking on the connections . When you find the hot one you found the bad one(s).  If  this has a starter with a magnetic switch and you have a 12 volt system you need 10.5 volta at the starter while the starter is cranking the engine.