Small Engines (Lawn Mowers, etc.): Craftsman 18.5 HP BS missing, craftsman lawn tractor, pop pop pop

Question
I have just recently started having trouble with my Craftsman lawn tractor. I bought the mower new a couple of years ago. Model No. 917.273631  B&S engine model number 31P777, type 0348-E1.  The story ...   A couple of weeks ago, one of the mandrels broke on me. Up to this point, the tractor was running like new. I removed the deck and replaced the mandrel myself. I also took this opportunity to spray out the deck and under the hood to remove all the loose grass. After this however, it has been missing bad (pop.pop.pop.pop....) when I have the mower fully engaged. If I let off the throttle/choke some it will smooth out. And it has lost power. I have the gearshift moved to '6' and it moves like it should in '3'. What I have done so far is replace the spark plug, fuel filter, removed the carb and cleaned it out good and attempted to adjust the fuel mix and idle screw. I even replaced the solenoid. It is still missing bad. It is not smoking at all. I have checked all the wires to make sure they are still connected. I have pretty much ran out of ideas. I would greatly appreciate any help you could give me.

Answer
Hello Tony:

You can View a Breakdown/IPL of the Engine at this Site Addy; http://www.briggsandstratton.com/maint_repair/manual_and_more/doclist.aspx?categ... and Enter the Model Numbers (31P777) and Type Numbers (0348) in the Appropriate Boxes and Click GO. Then Select Download PDF. First Lets get a Start Up Setting on the Carburetor Mixture Screws.  The Following it the Instruction File for Setting the Air Mixture Screws. Any Input that will Make this File Better is Appreciated. The Procedure is the Same for 1 or 2 Mixture Screws, Just Use the Instruction File and Skip Over the Section with the Missing Mixture Screw. Now Setting the Air Mixture Screws:  ****Turn the Idle Air and Main Air Mixture Screws In Until SNUG **Do Not Jam** Then Reverse Both Screws 1 1/2 Turns. Holding the Throttle Full Open, Start the Engine. Turn the Main Air Mixture Screw Clockwise Until Proper Revs are Obtained. Occasionally you May have to Turn this Counter Clockwise to Achieve the Proper Revs. Now Allow the Engine to Idle. Set the Engine Idle Screw (Not Idle Air) so the Engine will Stay Running if Required. Now Set the Idle Air Mixture Screw so there is No Hesitation when Throttling from Idle to Full Throttle. Reset the Engine Idle if Required.**** Have you Checked the OHV Clearance? If the Valve Clearances are Not Correct, you can have the Pop you Described. **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) on the Compression Stroke When Setting the Valve Clearance. Now Loosen the Valve Adjuster Locks and Set the Intake Valve Clearance to .004in -.006in and the Exhaust to .007in - .009in. 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 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. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

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Respectfully

John