Small Engines (Lawn Mowers, etc.): Craftsman Lawn Mower Starts but Cuts Out, spark plug gap, craftsman lawn mower

Question
Hi John:

I have a Craftsman purchased in 1995 which is almost brand new but has not been used much at all. The model number of the lawn mower is a 3 in One convertible, model 944365060 while the engine is a 4 cycle 5.5 HP model 143.955502. After it sat for a few years I tried to start it recently.    It was dead.  I changed the spark plug.  Then it would start, run for about 3 seconds and then stop. Note, that during this time there was quite a bit of grey smoke from the muffler.   

I then fully drained the oil which had been in there for a few years and replaced it.  The oil was very black.  I also topped up the gas but I did not fully drain the gas tank.  I also confirmed that the spark plug gap is ok and the air filter is clean.    I tried to start it again and the same thing.  It runs for about 3 or 4 seconds and then cuts out.   

Any idea how to fix it?   By the way, I am not an engine expert and have never fully taken one apart before.  When providing your solution, please let me know your opinion on how complex it would be for a non-expert like me to disassemble it, fix it, and put it back together.

Thanks very much for your help John!

Ron

Answer
Hello Ron:

From your Description, it Sounds like the Carburetor need to be Cleaned. I have Found that Most People can Rebuild the Carburetors with a Breakdown and Instructions. Also, Since this is a Tecumseh Engine, I have 2 PDF Site Addys that May Assist you Also. They are; 1- http://www.tecumsehpower.com/CustomerService/BSI.pdf and 2- http://www.cpdonline.com/692509.pdf You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the T. Then Select Tecumseh. Then Select Don't have Part Numbers. Then Enter the Model Numbers. Then Select your Model and Download the File for Online Viewing. You should Find a Breakdown of the Carburetor at the PDF Sites I Provided. I have Also found that Taking Pictures as the Carburetor is Disassembled is a Good Idea. It Helps if you Lose the Online Breakdown. Kind of a Backup Plan. 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 you Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John