________________________________________________________________________________________

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.

________________________________________________________________________________________

________________________________________________________________________________________

Engines Technical Specifications
BRIGGS 28S777 BRIGGS 31H777 BRIGGS 31P977 BRIGGS 31Q777
HONDA GC135 HONDA GCV160 HONDA GS190 HONDA GX340
KOHLER CH18S KOHLER CH680 KOHLER CV460S KOHLER SV735S
KUBOTA D1305 KUBOTA D1503 KUBOTA V1903 KUBOTA 2003T
MERCURY 150 MERCURY 175 XRI MARINER 135 MERCURY 200 EFI
KAWASAKI FH430V KAWASAKI FR600V KAWASAKI FX541V KAWASAKI FD611V
BMW M20B23 BMW M40B18 BMW M43B16 BMW M50B24TU
TOYOTA 3VZ-E TOYOTA 1AZ-FE TOYOTA 1G-FE TOYOTA 1JZ-GE
NISSAN HR12DE NISSAN A12 NISSAN A15 NISSAN CA18DET