Remove and sharpen the blade. If the blade is sharp, it will slice though the grass with no resistance. Over time, the cutting edge gets blunted by stones, grass and soil. If that doesn't fix it, remove the carburetor, strip and clean all the jets. Make sure you count the turns and write down any pilot jet settings.
Check the fuel lines. My brother had one that wouldn't start because when the fuel line was forced on to the fitting, some rubber shaved off the inside of the tubing and blocked the fitting. Also inspect the fuel filter and fuel cutoff or check valves if these are present.
I haven't looked up your particular model, but some riding mowers have fuel cutoff interlock devices. Check those for proper operation.
BRIGGS & STRATTON ENGINES:
For temperatures above 40? F use an SAE30W oil. Using multigrade oil may increase oil consumption. Using SAE 30W oil below 40? F will result in hard starting and possible engine
bore damage. For temperatures below 40 ? F use
an SAE10W-30 or SAE5W-30 oil. Oil capacity for the 6 H.P. engine is approximately 5/8 quart (20 ounces; 0.6 liter).
Refer to Briggs & Stratton engine owner's manual for additional
information.
It's goose is cooked. or notsee long play below.I assumed that was done first,.or the blade engage lever is disengaged now and the engine pulley to blades is relaxed, the engine may have cracked the rod or crank shaft.
Rotate the engine in the direction it runs, since the stroke sequence is intake, compression, power, exhaust, the exhaust valve will open and close followed closely by the intake. After the intake opens and closes there will be a pause before the exhaust opens and closes again.
Remove spark plug Remove cover from engine that covers the flywheel Remove rockerarm cover or valve cover Find TDC (top dead center) by rotating the flywheel by hand and your finger over the spark plug hole as you rotate the flywheel you will feel pressure against you finger at some point then stop. This is the compression stroke it is called now find a long slim round piece of plastic or plastic ink pen to stick in the spark plug hole (If you are careful a slim screwdriver can be used ) and find the piston top, then slowly rotate flywheel again (cw) as the piston is moving up pushing the plastic up as you rotate the flywheel slowly. a max. piston up or tdc as you turn you will feel and then the piston starts to go the other way,at that transition this is tdc (piston is on top of stroke) leave it there,,both valves should be closed at that point. Have a feeler gauge and set the exhaust valve at a loose .002 and the intake a loose .004 be sure engine is cold when valves are adjusted Feeler gauge goes in between the rocker arm tip and valve stem top for each valve setting. Note the rocker adjustment at the push rod side of each valve by tightening and loosening to make adjustments,lock your adjustments in place and rotate flywheel a few times and recheck settings
Surging is most often caused by lean air fuel mixture. Older adjustable carbs were easy to dial in by simply following procedure to adjust. Today's non adjustable ones are more challenging first make sure all carb passages are clear and your carb is crud free then if surging persists and carb is equipped with a choke try choking it little by little if it smooths out with choke on you know your air fuel mixture is lean. To fix you will need a set of micro drill bits to enlarge passage in air jet usually located on top of carb near throttle shaft or main jet at fuel nozzle inside carb. First find bit that fits current hole then carefully drill it to the next size larger. You may need to do this 2 maybe 3 times to smooth it out but don't overdo it. After making sure carb isn't just dirty I usually start with the air jet on top.sometimes that's all it takes
Intake and Exhaust Clearances for Briggs & Stratton engines used on a variety of outdoor power ... Model Series, Engine Type, Intake Valve Clearance ( in. ) ...
Missing: 126t02 ' Must include: 126t02
WARNING: Always read the engine and equipment manual(s) before starting, operating, or servicing your ... Adjusting Tappet Clearances & Overhead Valves.
Edited the question for spelling and clarity and moved you to the right category. The answers are here
https://www.google.com/search?q=20hpintek+surgine
