Here are some possible culprits and the questions you should ask yourself to figure out what might be wrong:
1. Engine Mechanical Issues:
* Valve Timing: Incorrect valve timing can cause the engine to seize.
* Question: Have you recently adjusted or worked on the valves?
* Compression Issues: Low compression can make the engine struggle and lock up.
* Question: Is there good compression in all cylinders? (Use a compression tester to check)
* Seized Bearings: If the crankshaft bearings are worn or seized, the engine won't turn smoothly.
* Question: Is there any unusual noise or resistance when rotating the crankshaft by hand?
* Broken Piston Rings: Broken piston rings can cause a loss of compression and potential engine damage.
* Question: Is there any unusual smoke or blow-by coming from the engine when running?
* Broken Connecting Rod: A broken connecting rod is a serious problem that can cause the piston to seize against the cylinder wall.
* Question: Is there any unusual noise or rattling coming from the engine?
* Foreign Object in Cylinder: A foreign object in the cylinder can damage the piston and prevent the engine from running.
* Question: Have you recently done any maintenance that might have introduced foreign objects?
2. Ignition Issues:
* Spark Plug Problems: A fouled or faulty spark plug can prevent the engine from running smoothly.
* Question: Have you recently changed the spark plug? Is the gap on the current plug correctly set?
* Ignition Coil Failure: A faulty ignition coil won't provide a strong enough spark to ignite the fuel.
* Question: Is the ignition coil functioning properly? (Check with a spark tester)
* Timing Issues: Incorrect timing can lead to a misfire or complete engine failure.
* Question: Has the ignition timing been adjusted recently?
3. Fuel System Issues:
* Fuel Contamination: Contaminated fuel can cause engine problems, including locking up.
* Question: Is the fuel fresh and clean?
* Fuel Filter Clogged: A clogged fuel filter can restrict fuel flow and cause engine issues.
* Question: Have you recently checked or cleaned the fuel filter?
* Carburetor Problems: A dirty or malfunctioning carburetor can lead to a lean fuel mixture or flooding, which can cause engine problems.
* Question: Have you recently cleaned or adjusted the carburetor?
Need More Information:
To get more specific help, you need to provide additional details about the problem.
* Describe the problem: Does the engine crank but not start? Does it start but immediately die? Does it start but run roughly?
* What have you done already? Have you checked the obvious things, like fuel, spark, and compression?
* What is the history of the engine? Have you recently done any maintenance or repairs?
I recommend consulting your Briggs & Stratton engine's manual for troubleshooting steps and contacting a qualified mechanic for further assistance if you can't resolve the issue yourself.
