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| Home / Engines / Briggs and Stratton Engines / Briggs and Stratton 31P977 |
Briggs and Stratton 31P977 Problems
| Engine Model: Briggs and Stratton 31P977 |
| Engine Type: 4-cycle single cylinder OHV vertical shaft gasoline engine |
| Total Displacement: 30.6 cu.in (501 cc) |
| Rated Engine Power: 20 Hp (14.9 kW) at 3600 rpm |
| Fuel System: Float type carburetor with fixed main jet |
| Engine starts hard or will not start |
Empty gas tank - Fill fuel up.
Wrong grade of gasoline - Change gasoline.
Dirty fuel lines - Inspect and clean.
Damaged spark plug wiring connection - Check the spark plug wire connection, repair or replace.
Spark plug is defective - Install new spark plug.
Fuel filter is plugged - Fuel filter needs changing.
Brake pedal not pushed down - Push the brake pedal down.
Carburetor not adjusted - Adjust according to instructions.
Weak cylinder compression - Inspect cylinder block and change worn parts.
Damaged or not adjusted choke cable - Adjust properly or replace the cable.
| Irregular engine running |
Clogged cooling fins - Need to clean or wash.
Ignition system problems - Check ignition system and replace faulty parts.
Throttle cable is faulty or stuck - Change or clean the cable.
Air filter element is clogged - Change or service air filter.
Dirty or damaged fuel pump - Test fuel pump and change if necessary.
| Engine starts but stops suddenly |
Spark plug is defective - Install new spark plug.
Carburetor is dirty or defective - Clean or replace carburetor.
Ignition coil is not working - Change ignition coil as required.
Valve springs are weak or broken - Install new valve springs.
Stuck valves - Service the valves.
| Engine overheated |
Engine oil level is insufficient - Checking oil level and add if necessary.
Engine overload - Load reducing required.
Air intake screen is plugged - Need to clean or wash.
Too lean carburetor mixture - Adjust carburetor correctly.
Improper ignition timing - Set the ignition timing properly.
Valve setting is incorrect - Valves needs to be adjusted properly.
| Engine knocking or noise |
Stale or low octane fuel - Change fuel.
Engine is overloaded - Load reducing required.
Engine oil level is insufficient - Fill the crankcase with engine oil.
Wrong adjustment of low idle speed - Need to adjust idle speed.
Fuel pump is defective or dirty - Test fuel pump and change if necessary.
Worn main bearings or crankshaft - Have bearings or crankshaft replaced.
Excessive valve clearance - Adjustment procedure required.
Damaged piston rings or cylinder bore - Replace faulty components.
| Engine loses power |
Carburetor is clogged or improperly adjusted - Adjust the carburetor correctly or clean it.
Air filter element is clogged - Clean or change air filter.
Dirty or faulty fuel pump - Test fuel pump and change if necessary.
Ignition system is defective - Check ignition system and replace faulty parts.
Defective cylinder head gasket - Change cylinder head gasket.
Stuck or burned valves - Clean or change valves.
Worn or bent push rod - Change push rod.
Cylinder block parts are damaged - Replace defective parts.
Dirty oil filter element (if equipped) - Replace or clean oil filter.
| High fuel consumption |
Insufficient throttle opening - Adjust or replace throttle cable.
Carburetor main jet is improperly adjusted - Adjust it properly.
Spark plug is loose or faulty - Change or re-tighten spark plug.
Worn, stuck, or burned valves - Service or change valves.
Worn piston, rings, or sleeve - Change defective parts.
Excessive valve clearance - Adjustment procedure required.
| Engine using too much oil |
Worn seals or gaskets - Defective components must be replaced.
Worn valve guides and valve stems - Valves need to be changed.
Worn or stuck piston rings - Piston rings replacement required.
Cylinder liner or piston is scored - Check liner and piston, change as required.
Blocked breather hose or pipe - Change or clean.
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