I replaced an old Mercury starter on my outboard with an Arrowhead product. Turns out the distributor that sold it to me made a mistake - there were two gear sizes for the same starter and they sent the wrong one. I called Arrowhead, they were quick to note the mistake and sent me a new one immediately, with pre-paid return for the one I had received from the dealer.
On mine, what I discovered was that the helix channeling that allows the starter gear to move out to the flywheel was slightly "burred" from machining and the gear would stick in the "engaged" position. In other words, when the starter motor quit spinning, the gear should drop back to it's neutral position and mine would not - it took a few trips out, but I was stingy with the oil and a synthetic brush and now it works just fine. Would have been a great purchase for me a few years ago, instead of last year.
