Small Engines (Lawn Mowers, etc.): Briggs 446777 Engine, blown head gasket, dark gray color

Question
QUESTION: My cousin has a Craftman mower that is equipped with a 26 HP Model # 446777-0244-E1 engine. He lost compression on the right side cylinder and he purchased an engine from a gentleman from ebay that says he is a master tech. I installed the engine for him and upon start up it blew smoke out the exhaust, we figured it was just from the old engine having dumped oil out into the exhaust. We let the mower sit for a few days and took it out to try it and when he puts a load on the engine, it really smoked bad. After 30 minute of mowing, we checked the oil level and it was down a quart. We added more oil and he mowed in taller grass putting more strain on the engine and after 15 minutes, it was down 1/2 a quart. We emailed the guy he bought the engine from and he said to put some Deep Creep in the cylinders and that he bench tested it and did a leak down test and everything was good and in spec like a new craftman engine. When I took out the spark plugs they were all black with carbon and the right side one is wet with oil. We tried the Deep Creep like he said to do but still smoking bad and its a dark gray color. Any ideas on why its doing this? He bench tested it with no strain on the engine but once there is strain, it starts smoking bad. Thank you for your time.

ANSWER: Hello Mark:

If the Smoke is Black, then the Carburetor is Too Rich when a Load is Applied. If Blue Smoke or White/Blue Smoke, then this is Oil. You May have a Blown Head Gasket Between the Compression Chamber and the Valve Stem Galley. This will Cause the Engine to Smoke Also. If the Head gasket is Good, then There May be a Ring Problem. Check the Compression First and then Check the Cylinder with the Lowest Pressure. From your Description, it Sounds like the Cylinder with the Oil on the Plug is the Blown Head Gasket. The Other Plug will be Black from the Excess Gas that is Left in the Intake from the Blown Head Gasket on the Other Cylinder. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

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: When I took both heads off, there was alot of excess oil in the cylinders. I replaced both head gaskets and intake valve seals and it still is smoking about the same as before. Is it safe to assume that its probably the rings as there was all that oil in the cylinders. Seemed like there was more oil in #2, and number 1 had alot of oil on top of the piston. I had a Briggs and Stratton service guide right in front of me at all times, so I torqued the head at the proper specs and in order. I followed everything to a T. On the lighter side, it starts right up at the tap of the key now. :)

Answer
Hello Again Mark:

It is Possible a Ring has Frozen (Stuck) and is Not Flexing as Designed. Add 2oz Marvel Mystery Oil to the Crankcase Oil. This will Help the Rings if One or More has Frozen/Stuck. Have you Cleaned the Crankcase Breather? It May have Oil in it and Requires Cleaning in Order to Operate Properly. If the Above Items Do Not Correct the Problem, then the Rings are Most Likely Worn. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John