http://autos.yahoo.com/maintain/repa...ques093_4.html

Hot starting problems can also be caused by cooling problems that allow your engine to run too hot (the pistons swell up and may scuff the cylinder walls), or excessive resistance in the starter motor that causes*the engine*to crank slowly. A starter "amp draw" test can be used to check the condition of your starter. Also, many starters have small "heat shields" to protect them from heat radiating from nearby exhaust pipes or manifolds. If the shield is missing, the starter may get too hot and bind up.*