Outer Limits 4x4 Board

G'day, recently my old starter motor died, so I went to the wreckers and picked up a second hand one for a decent price. The guy tested it for me before I took it and it worked fine. I fitted the starter motor myself about a month ago. Initially it worked well, but now when I start it, it is making that loud grinding noise more and more. In the mornings, Sometimes I have to try 3 or 4 times just to get my starter to turn the engine over. Is this a sign that the starter motor I got was already worn out, or have I fitted it incorrectly? Thanks for any advice, Sam

1st thing would be to check the earth ead at your battery then make sure the terminals to the battery are in perfect condition, give them a sand up. They draw alot of current so connections need to be spot on.