Small Engines (Lawn Mowers, etc.): Lawn Tractor wont start, twin cylinder engines, compression stroke

Question
I have a Craftsman DYT4000(new in 2004)with a 18.5 B&S intek ehgine. Always been a workhorse and very reliable. Plow snow in winter with it. This winter it has been startin slowly: turns over for 10-15 seconds, a loud backfire, then it starts kinda roughly. Thought I may need a new battery(not sure why), so I replaced the original with a better one(more CCA). First time I used it it started a little better. Last week I got it out to plow snow and it just cranked and cranked but would not start. No backfire at all. I ran the battery down and now I will most likely need to jump it off my car(both 12 volts). I have Mobil 1 10W30 oil in it, which is what I have used every year. I know it's either an electrical or fuel delivery problem. Is there an electrical component on this B&S engine that would fail after 4 yeasr of use? Regulator, magento? What is your best guesses as to why my old reliable won't start well anymore. It fired right up every time this past summer. Many thanks.

Answer
Hello Randy:

>>Check the Valve Clearances.
>>The Following is a Basic File I made for Setting the Valve Clearances. Any Input is Appreciated.
>>**I Do Not Use the Setting Called for by the OEMs. I have Found that the Following Works Best.
>>Remove the Valve Cover (on the Dead Cylinder for Twin Cylinder Engines).
>>Set the Cylinder you are Setting the Valves on to Top Dead Center on the Compression Stroke When Setting the Valve Clearance. Now Loosen the Valve Adjuster Lock and  Using a Blade Style Feeler Gauge, Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .004in - .006in. Loosen and Tighten the Rocker Arm and the Feeler Gauge is Placed Between the Rocker Arm and the Valve Top where the Rocker Arm Pushes on the Valve.
>>***BE SURE TO TIGHTEN THE ADJUSTER LOCK AFTER YOU HAVE THE PROPER VALVE CLEARANCE.***
>>I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings.
>>**Be Sure the Piston is at TDC on the Compression Stroke.** If you Remove the Valve Cover and then Turn the Engine by Hand, you can Watch the Intake Valve Movement. When the Intake Valve Closes, the Piston will Just Starting the Compression/Power Stroke.
>>On Some Engines you can Us a Straightened Coat Hanger and Feel the Piston. Be Careful and Don't Jam the Wire in the Cylinder. Usually the Piston will Push the Wire Out of the Spark Plug Hole with No Problems.
>>Please, Do Not Hesitate, If you Hit a Snag, if I Missed Something or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. 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 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John