Small Engines (Lawn Mowers, etc.): Briggs and Stratton 16.5 OHV, twin cylinder engines, briggs and stratton

Question
Hey John I have a Murrary 42" with a 16.5 Briggs and Stratton engine. When I first got it, no problems, then the battery went dead. Replaced the battery, it ran fine about two times, then the battery was dead again. Bench tested the starter (okay), new selonoid, and got a new battery. After that it would only crank very slowly and then stop. I adjusted and cleaned out the vavles. Now when I try to start it, the thing just turns and turns like it wants to start but just won't. After about 30 seconds I will get a back fire through the muffler. Everything appears good, sprayed carb cleaner into the bowl of the carb, but it just starts to shot out the muffler and backfires. Any suggestions?? Fresh oil, good spark, and nothing....

Answer
Hello Jim:

Check the Valve Clearances and Make Sure they Are Set Correctly. 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 (Both Rocker Arms will have Play in them when the Engine is at TDC) When Setting the Valve Clearance. Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .008in - .010in. I have had Better Performance Out of the Mowers and Less Burnt Valves Using these Settings. If the Valve Clearances are Correct, then Check the Flywheel Key. If the Flywheel Key is Damaged it will Cause the Problem you Described. ***Remove the Blower Housing (metal engine cover). Remove the Flywheel Nut or Starter Cup (Depends on the Model). Now Attach a Steering Wheel Puller to the Flywheel Using the Threaded Holes in the Flywheel. Tighten the Puller. Now Hit the Puller with a Hammer. Repeat this Procedure Until the Flywheel Pops Up or can be Lifted Off the Crankshaft. On Some Models you Can Not Use a Puller and Must Use a Pry Bar and a Pipe Cap that is Slightly Larger than the Crankshaft. Place the Pipe Cap Over the Crankshaft to Protect it. Place the Pry Bar Under the Thick Section of the Flywheel and Pull Up Against the Flywheel. **BE CAREFUL  DO NOT PUT A HOLE IN THE BLOCK UNDER THE FLYWHEEL** Now Hit the Pipe Cap that is on the Crankshaft (covered with the Pipe Cap). Repeat the Procedure Until the Flywheel can be Lifted Off the Crankshaft. *** If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. 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. Thanks.

Respectfully

John