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| Home / Engines / Briggs and Stratton Engines / Briggs and Stratton 31R977 |
Briggs and Stratton 31R977 Problems
| Engine Model: Briggs and Stratton 31R977 |
| Engine Type: 4-cycle single cylinder OHV vertical shaft gasoline engine |
| Total Displacement: 30.5 cu.in (500 cc) |
| Rated Engine Power: 17.5 Hp (13 kW) at 3600 rpm |
| Fuel System: Float type carburetor with fixed main jet |
| Engine starts hard or doesn't start |
Empty gas tank - Add fuel.
Incorrect fuel grade - Change gasoline.
Clogged fuel system - Remove clogging.
Defective spark plug wire connection - Inspect the spark plug wire connection, replace or repair.
Spark plug is damaged - Replace spark plug.
Fuel filter is clogged - Fuel filter needs to be replaced.
Faulty safety switch - Change damaged switch.
Carburetor problems - Carburetor diagnostics required.
Low compression - Check and replace worn parts.
Damaged or incorrectly adjusted choke cable - Adjust correctly or change the cable.
| Rough engine running |
Plugged cooling fins - Need to clean or wash.
Ignition system is defective - Inspect ignition system and change failed components.
Defective or stuck throttle cable - Service or change the cable.
Air filter is blocked - Clean or change air filter.
Fuel pump is damaged or dirty - Service or change fuel pump.
| Engine starts and stops |
Spark plug is defective - Spark plug need to be replaced.
Carburetor is dirty or defective - Clean or change carburetor.
Ignition coil is damaged - Change ignition coil as required.
Broken or loose valve springs - Replace valve springs.
Stuck valves - Clean the valves.
| Engine keeps overheating |
Engine oil insufficient - Fill up the engine oil.
Excessive engine load - Reduce the load.
Air intake grill is clogged - Need to clean or wash.
Carburetor mixture is too lean - Use proper settings.
Incorrect ignition timing - Set the ignition timing correctly.
Wrong valve setting - Adjust valves as required.
| Engine knocking or noise |
Stale gasoline - Use correct fuel.
Engine overload - Reduce the load.
Insufficient engine oil - Add oil to the engine crankcase.
Low idle speed setting is not correct - Test and adjust.
Fuel pump is damaged or dirty - Service or replace fuel pump.
Main bearings or crankshaft wear - Change or repair worn components.
Incorrect valve clearance - Adjust valve clearance according to specifications.
Worn piston rings or cylinder bore - Replace faulty parts.
| Loss of engine power |
Carburetor is incorrectly adjusted or clogged - Adjust the carburetor correctly or clean it.
Plugged air filter - Service or change air filter.
Fuel pump is defective or dirty - Clean or install new fuel pump.
Defective ignition system - Inspect ignition system and change faulty parts.
Cylinder head gasket is blown - Install new head gasket.
Valves are burned or stuck - Service or replace valves.
Worn or damaged push rod - Replace push rod.
Damaged cylinder block parts - Replace defective components as required.
Plugged oil filter (if equipped) - Clean or change oil filter.
| Engine using too much gasoline |
Choke doesn't open well - Adjust or replace choke cable.
Improper carburetor main jet adjustment - Adjust it properly.
Loose or faulty spark plug - Spark plug need to be tightened or replaced.
Valves are worn, stuck, or burned - Replace or clean valves.
Worn sleeve, piston, or rings - Replace faulty parts as required.
Valve clearance is improper - Adjust to proper valve clearance.
| High oil consumption |
Defective seals or gaskets - To repair leaks, replace worn parts.
Damaged valve guides or valve stems - Replace the valves.
Worn or stuck piston rings - Change the piston rings as required.
Cylinder liner or piston is scored - Inspect piston and liner, fit new components as necessary.
Breather hose or pipe is blocked - Clean or replace.
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