The starter motor wears out much more with a two-cylinder engine compared to a four-cylinder engine with a two-liter displacement, especially if an exhaust cam is pushing down the hydraulic tappet. It takes at least five engine revolutions to bleed the hydraulic tappet so the camshaft can act as a decompression mechanism. I'm on my fourth starter motor since 2013: two LF9H-18-400 M000T37471 starters and two aftermarket ones.
