Small Engines (Lawn Mowers, etc.): Briggs 22hp 407777, blown head gasket, exhaust smoke

Question
The engine was backfiring, running rich to the point it fouls out the plugs within minutes. Took it to a repair garage where they replaced the head stating the problem was caused due to a sticking valve. I had a hard time understanding how this would have effected both cylinders, but ensured me it did. $400 later it runs like a top for about 2 months, the problem is back to its original glory, plugs last about 15 minutes, black smoke pouring out of it. When checking the compression, one side is at 130, the other 150. What now? The tractor only has 400 hours on it. Oil changed every 50 hours. I just cant believe another head is bad. Model 407777, type 0128E1 code 000929YH.

Answer
 Hello Joe:

 The Low Compression; Is it on the Head that was Replaced? Has Anyone Checked the Carburetor for Flooding? Dark Black Smoke is a Sign of Too Rich Gas. A Blown Head Gasket or Sticking Valve will Not Cause this to My Knowledge. A Sticking Valve will Cause a Miss though and you Didn't Say Anything About a Miss; Just Black Exhaust Smoke and Plug Fouling Black in Color. Go to this Addy http://shop.briggsandstratton.com/BShopProductListingPage.asp?rsvp=0&PARENTID=0&... and Enter the Model Numbers 407777 and the Type Numbers 0128 and Click Search. The Select the View PDF. This will Download a Breakdown/IPL for you to View Online. If you can, I Suggest you Purchase a Gallon Can of Gunk Carburetor Cleaner. Remove and Disassemble the Carburetor and Soak it Overnight in the Gunk. Then Blow Out the Passages with Compressed Air and Install New Kit. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John