I have a 2004-built (purchased June '05) Cub Cadet LT1018 with an 18 HP Kohler Command engine. It's always seemed like a bit of a weak starter. For the past few years, at times, I'll turn the key, and the engine will lurch as the starter tries to turn, then after a second or two it starts turning the engine -- weakly.
It sounds like a weak battery, but the one it has now is only a couple years old, and this happens even with a new battery, after a few weeks. Plus the voltmeter is always just under 12 volts, like 11.7-11.9.
Meanwhile, my grandfather has a Craftsman with an 18 HP Briggs Intek that was new in 2007 and replaced the battery last year. That thing cranks very strongly and requires much less cranking time to start than my Cub.
Ideas for other parts in the electrical system to check besides the battery? Perhaps the starter itself? Is this a known issue with Cubs/Kohler Commands?