Motor starts up then it turns to sluggish like its missing. then it will shut down. Hard to start after.

you may need to turn the Hi screw on the carb in 1/4 of a turn. Make sure the gas and mix are fresh.

Bad ignition coil. You can try to find the OHM specs and test it but that is what happens when you have a failing coil.

Check plugs, may be fouled> When storing bikes in my old mans garage, the plugs always foul

Ensure clean fuel. Always use Stabile in fuel. Follow fuel line from fuel tan to carb, ensure no leaks. Remove carb fuel bowl to check float operation. Have pliers to crimp line or use fuel shut off valve. Remove carb float bowl and clean. Float should hang down freely gas should flow. Push float up gas should cut off. Replace spark plug, ensure plug wire snaps on tight. Clean or replace air filter. Ensure oil is full, 30w oil. All mowers have low oil shutoff.

Sounds like the carb is varnished up and needs to be rebuilt. They make rebuild kits depending on the carb number and you can rebuild it.

Backfiring out of the exhaust is usually an ignition problem. Unburned fuel is getting into the exhaust system because it's not being ignited in the cylinder. When the engine fires on that cylinder again, it ignites the raw fuel in the exhaust causing the pop that people call a backfire. I'd investigate the ignition system. Connect a timing light to each of the spark plug wires if it has a single fire ignition or either of them if the ignition system is the stock dual fire. Start the engine and watch the timing light to tell if the engine is missing as the light will miss a flash.

Good Luck
Steve

This usually is an indication that the needle valve in the carb (controls the amount of fuel to enter the carb from the tank) is stuck open or something has lodged in the needle valve to keep it from closing.
If you can pull the carb off the mower, carefully turn it upside down and remove the bowl. The float is attached to the needlle valve. If you're comfortable dismantling the carb, take the float loose by sliding the hinge pin out to one side, then carefully pull the float with the needle out of the valve body.
Don't lose any parts... it's best done on a workbench with a clean white rag under your work.
take a can of carb spray and clean the valve body and the needle valve...DO NOT attempt to probe the valve with a tool or clip...you may damage the seat and it'll leak forever ..
Once clean, reinstall and check your fuel filter to make sure there it's clean and keeping further dirt, residue out of the needle and seat ..
Before starting, pull the plug, and turn the motor over to clean the gas out of the cylinder... be sure to ground the spark plug wire so you don't jump a spark and start a fire..
Clean or replace the spark plug and double check to make sure the gas is getting shut off so it's not flooding the motor again..

clean MAF sensor with carb cleaner. disconnect battery for 2 hrs to clear memory. drive 10 miles to relearn

It sounds like the float is sticking in the carb. Since the carb is higher than the fuel tank it pulls the fuel in by vaccum of the engine. when running at high rpms, it can burn the fuel thats flowing into the carb, when you idle down, the bowl of the carb is filling up with fuel faster than the engine can burn it and causing it to flood. Then when it shuts off at idle it does not want to start back up because it is flooded. To make a long stary short, pull the carb and give it a good cleaning and your problems should be solved.

Drain the carburetor. There should be a screw on the lower side of the carb float bowl. Remove the screw then replace it after the fuel drains. Turn the gas back on and wait a minute for the carb to fill with gas. Install new stock spark plugs. If the bike doesn't start and run properly then shut off the gas and remove the carburetor from the engine.

Remove the float bowl and clean the entire carb with a spray carb cleaner from the auto parts store. Wear protective goggles to avoid getting spray in your eyes. Spray into all the little airways and fittings in the carb. This process should get you back on the road.

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