I have a 1992 E115TLEND and it seems the starter is having problems turning the motor over on the initial start. It engages but doesn't seem to have the power to turn it over. After a couple of tries it starts fine. Is the starter getting weak and is that what needs to be replaced? Connections seem to be tight and clean. Is there a way to test the starter to see if it's get weak? Any help would be appreciated.