Small Engines (Lawn Mowers, etc.): screeching, engine model type, briggs and stratton

Question
i have a mower that makes a screeching sound but it is not constant. it will run for a while after you start it then it will make the screech. then if you shut it down and restart it it will run for a while then screech again. would that be the same. it is an older murray mower with a briggs and stratton motor.  

Answer
This screeching sound is caused by the start clutch.  Don't continue to run it any longer as it can "grab" the starter pulley and break the recoil rope and/or spring.  It is best to replace the starter clutch as I have had no success with trying to clean and re-use.  Take the numbers from the engine (model, type and code) in when getting the new clutch.  Remember to also polish the end of the crankshaft with emery cloth before installing the new clutch.  Hope this helps.