Small Engines (Lawn Mowers, etc.): 14.5 HP BRIGGS ENGINE BLOWUP, blown head gasket, briggs stratton engine

Question
QUESTION: MY 14.5 HP BRIGGS & STRATTON ENGINE (MODEL:287707, TYPE 0255 01,CODE 960408 4A) STARTED BLOWING HUGE PUFFS OF WHITE BLUE SMOKE WHILE I WAS CUTTING SOME TOUGH GRASS. THE ENGINE DID NOT STOP RUNNING AND WAS RUNNING STEADY UNTIL I CUT IT OFF, WHICH WAS WITHIN 5 SECONDS. I SPUN THE ENGINE WITH MY HAND AND NOTICED NO APPARENT ENGINE DAMAGE. I STARTED IT RIGHT BACK UP, IT SMOKED FOR 30 SECONDS OR SO THEN RAN WITH NO APPARENT SMOKE. I FINISHED CUTTING THE GRASS IN ABOUT 20 MINUTES. NO MORE SMOKE. I THEN CHANGED THE OIL (CASTROL 20W50 WHICH HAD LESS THAN 10HRS). WHEN I LOOKED IN THE AIR FILTER I SAW THAT OIL HAD BLOWN INTO THE INTAKE AND INTO THE CYLINDER SOME OF WHICH WENT OUT OF THE EXHAUST IN LIQUID FORM.
HOW MUCH DAMAGE DO YOU THINK I HAVE AND WHAT NEEDS TO BE REPLACED?

ANSWER: Hello Rufus:

From your Description, it Sounds like the Crankcase Breather/Vent Stopped Operating for a Few Minutes. Did the OIl you Drained have a Gas Smell to it? Does the Engine Run Good Now? Thanks.

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John

---------- FOLLOW-UP ----------

QUESTION: THE OIL DID HAVE SOME SMELL OF GAS TO IT THOUGH IT WAS NOT VERY STRONG. I DID A BURN TEST WITH SOME ON A PIECE OF PAPER AND IT DID NOT READILY LIGHT. DO YOU THINK IT WAS BLOW BY FROM THE CYLINDER RINGS OR A BLOWN HEAD GASKET? I HAVE THOUGHT OF STARTING THE ENGINE AND THEN OPENING THE OIL FILLER TUBE WITH ENGINE RUNNING BUT I IMAGINE YOU MIGHT GET OIL SPRAY EVEN IN A PERFECT ENGINE. AS FOR HOW IT RUNS,  IT RAN AND HAD POWER AS IT ALWAYS HAS. IT IDLES STEADY AND AT SAME IDLE SPEED. I HAVE HAD THIS ENGINE ON MY RIDING MOWER FOR 12 YEARS NOW AND IT PROBABLY HAS 200 OR SO HOURS ON IT AND THIS IS THE FIRST PROBLEM OF ANY KIND WITH IT.
THANKS
ANSWER: Hello Again Rufus:

If the Oil was Not Over Filled and Had No Gas Contamination, then Clean the Crankcase Breather. You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.smallenginepartswarehouse.com/parts.asp and Select the Shop Online Parts Look Up. Then Select the Model Tab. Then Select the OEM and Enter the Model and Type Numbers 287707-0255. Then Double Click on the Model in the Results Area. Now you can Select the Section of the Engine you Wish to View. Select the Cylinder, Piston/Rings, Crankshaft, Sump, Kits File. The Crankcase Breather (#8) is Located on the Side of the Engine Block Behind the Carburetor. There is a Rubber Tube from the Carburetor Throat to Crankcase Breather. If All the Engine Did was Smoke an then Quit Smoking, then the Engine Should Not be Damaged. The White Smoke Usually is a Sign of Contaminated Oil in the Crankcase. The Smoking and then Quiting Without you having Performed Any Maintenance means the Crankcase Breather Stuck for a Few Seconds and Allowed Oil to be Sucked Into the Carburetor Causing the Temperary Smoking. If the Mower and Engine have Been Well Maintained, then the Engine Should Last for 20 to 30 Years Before Giving Major Problems. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John

---------- FOLLOW-UP ----------

QUESTION: THANK YOU JOHN FOR ALL YOUR HELP. I CAN'T SAY ENOUGH ABOUT YOUR EXPERTISE. I DON'T MEAN TO BELABOR THE POINT BUT I HAVE ONE LAST QUESTION. I WANT TO BE SURE IT IS NOT A HEAD GASKET BEFORE I TACKLE THE CRANK CASE BREATHER MAINT. IF IT WERE A BLOWN HEAD GASKET WHAT SYMPTOMS SHOULD I LOOK FOR AND WOULD IT BE AS SIMPLE AS REMOVING THE HEAD AND BOLTING BACK UP WITH A NEW ONE INSTALLED TO REPLACE? WOULD THERE BE ANY ISSUES WITH GETTING THE VALVES OR LIFTERS BACK IN PLACE TO DEAL WITH?

Answer
Hi Rufus:

No Worries. Look at the Breakdown at the Site Addy I Provided Earlier. Other than Adjusting the Valve Clearance, you Remove the Rocker Arms and then the Head Bolts and Replace the Head Gasket. The Lifters are Inside the Engine Block. Usually the Head Gasket will Cause the Engine to Smoke All the Time Due to the Blown Section Between the Valve Stems and the Cylinder. If the Engine Smokes when On an Incline or Making Hard Turns, then the Crankcase Breather is Usually the Cause. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John