As some have seen, I recently acquired a M-F 135 with 4 cyl gas engine. When I got it, the starter would engage just enough to start as long as it started quickly. Otherwise, it would disengage very quickly. After reading, I assumed it was the starter drive getting weak so I just replaced it and the brushes as well. Now it won't engage the flywheel at all. Here's the kicker: on the tester at my local part store, the drive kicks in fully and tests good. I've swapped batteries, solenoids, even used a booster pack on the battery with no luck. The # on the Delco starter is 1107694. I have already ordered a reman starter ($50), but am worried it may not fix the issue. Any ideas?