Small Engines (Lawn Mowers, etc.): Rough idle, head gasket, ohv engines

Question
Hi John,

I trying to fix a Murray 6HP 20" lawnmower. Model 20606x30c. This machine starts and runs, however, it does not idle very well. I idles like a wave, high/low. I have drained the fuel, I have clean the carb (I did not use Carb cleaner, just a rag with gas). Yet, the problem did not go away. When you manually throttle, i can here misfire. Any ideas?

Answer
 Hello Frank:

 1- The Carb Needs to be Cleaned and All Ports and Passages Blown out with Compressed Air. 2- The Valves may Require being Reground and Lash Set. 3- A Head Gasket Leaking into the Valve Ports is a Common Problem with the OHV Engines. ReClean the Carb First. Hope this Helps.

 Good Luck

 Respectfully

 John