Starter problem

[SMatson802@aol.com]

My starter "releases" too early.  Just as the engine starts to fire, the 
starter disengages.  Not too much of a problem in warmer weather, but in 
winter, it was very difficult to get the thing going.  It was very close, but 
just wouldn't get started enough to keep running.  Is this just a weak or 
broken spring in the starter?  Is it hard to repair?  
Thanks,
Steve