Small Engines (Lawn Mowers, etc.): craftsman lawnmower doesnt run, engine 143, funny noises

Question
Craftsman selfpropelled lawnmower
6.75HP, Model # 917.377593
Engine: 143.996704
       WTPXS.2071BA

Just recently, this lawnmower stopped running. I've had it for about 6-7 years now and had no problems up until now. One day while I was cutting my grass it made this terrible clinking sound and I thought I hit a stump or something but when I stopped it, I checked to see what I hit and there was no stump or anything that could've hit the blade. So I started it back up and continued to cut the grass and not even 10 minutes later the engine started making some funny noises and since I didnt want to screw it up even more I decided to stop it. I had my dad look at it since he was automotive mechanic and had a good idea of how to fix engines. He ended up taking apart to see if there were any broken gears, and he didnt find any. He put it back together and tried to start it. After several attempts it finally worked but its much noiser, the vibrations are much stronger and it still makes the clinking sound. The blades fine, I checked it. After about a half hour of use, it stopped again. And I am unable to get it to start back up. Any suggestions?

Thank you for your time!

Answer
 Hello Larry:

 The Recoil Paws will Clink as you put it and it can be unnervering too. Check the Plug for Fire. The Coil May be Heating Up and Grounding. When this Happens, the Coil will Cool and then you can Restart the Mower. Hope this Helps. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John