Fixing a Briggs and Stratton Pull Spring

This shows how to do a easy repair on a broken Briggs & Stratton pull rope spring.  This is the old type of cap, the newer one is a lot simpler, and usually all it takes is unscrewing the ratchet assembly and benting (or rebending) a new hook in the end. 
Here's a broken spring.  They almost always break off close to the inner end.

Notice how the outer part of the spring has a wasp waist on it.  We need to grind a copy of that onto the inner broken end.  I usually use a fine grinding wheel, but I guess you could use a file or Dremmel tool. It doesn't have to be perfect, just fit into the inner hub with a twist.

Then, how do you rewind the spring?  It's EASY!  You use the cap of the mower as the rewind tool.  feed the spring in from the outside.  Latch the spring into the pull rope pulley. Put the pulley back into the cap and bend the little holders back over to hold it.  Now it looks like this:

Then you wind the spring into the cap using the pulley.  When the end gets to the slot it should click into the deeper section and lock itself there.

So now you have the spring ready to go!  Next, you have to redo the pull rope
Click here to see how to redo the rope