stalling

My LHS has the same problem, most especially when it's cold. After 4 starters, I have learned that the starters are freezing up in the engine. If I pull the starter and give it some power to run the motor unimpeded, then it unlocks and continues working for awhile. But eventually it wears out. Either the starters are not big enough for the engine, or the engine takes too much torque to start as it gets older.