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| Home / Engines / Briggs and Stratton Engines / Briggs and Stratton 31P777 |
Briggs and Stratton 31P777 Problems
| Engine Model: Briggs and Stratton 31P777 |
| Engine Type: 4-cycle single cylinder OHV vertical shaft gasoline engine |
| Total Displacement: 30.6 cu.in (501 cc) |
| Rated Engine Power: 18.5 Hp (13.7 kW) at 3600 rpm |
| Fuel System: Float type carburetor with fixed main jet |
| Engine won't start or difficult to start |
Gas tank is empty - Fill it up.
Incorrect fuel grade - Change gasoline.
Air trapped in fuel system - Bleed air.
Disconnected or loose spark plug wire - Inspect spark plug wiring connection, change or repair.
Damaged spark plug - Change spark plug.
Fuel filter is dirty - Replace fuel filter.
Safety contact for brake pedal defective - Install new part.
Carburetor incorrectly set - Set carb correctly.
Bad compression - Check and change damaged parts.
Damaged or not adjusted choke cable - Adjust properly or replace the cable.
| Engine runs unevenly |
Plugged cooling fins - Clean and wash as required.
Defective ignition system - Check ignition and replace faulty components.
Faulty or stuck throttle cable - Clean or change the cable.
Air filter is dirty - Clean or replace air filter.
Dirty or damaged fuel pump - Clean or change fuel pump.
| Engine starts but then stops |
Damaged spark plug - Change spark plug.
Carburetor is clogged or faulty - Repair or clean carburetor.
Damaged ignition coil - Install a new ignition coil.
Damaged or weak valve springs - Install new valve springs.
Valves are stuck - Valves need to be cleaned.
| Engine overheats |
Insufficient engine oil - Add oil to the engine crankcase.
Engine overloaded - Reduce load.
Air intake screen is blocked - Need to wash or clean.
Too lean carburetor mixture - Use proper settings.
Wrong ignition timing - Ignition timing needs to be adjusted correctly.
Valve setting is wrong - Valves needs to be set correctly.
| Engine knocking sound or abnormal noise |
Stale fuel - Use proper fuel.
Engine overloaded - Reduce the load.
Lack of engine oil - Check and refill engine oil.
Incorrect low idle setting - Need to adjust idle speed.
Dirty or damaged fuel pump - Test fuel pump and change if necessary.
Worn main bearings or crankshaft - Have bearings or crankshaft replaced.
Incorrect valve clearance - Adjust to proper valve clearance.
Piston rings or cylinder bore are worn - Replace faulty components.
| Engine lacks power |
Incorrectly adjusted or dirty carburetor - Service or correctly adjust carburetor.
Clogged air filter - Service or replace air filter.
Dirty or damaged fuel pump - Test fuel pump and change if necessary.
Ignition failure - Check ignition and replace faulty components.
Defective cylinder head gasket - Replace the gasket as required.
Valves are burned or stuck - Replace or service valves.
Bent or worn push rod - Replace push rod.
Cylinder block parts are worn out - Defective parts need to be replaced.
Oil filter is dirty (if equipped) - Service or change oil filter.
| High fuel consumption |
Insufficient throttle opening - Adjust or replace throttle cable.
Incorrect adjustment of carburetor main jet - Adjust the carburetor main jet correctly.
Defective or loose spark plug - Re-tighten or replace spark plug.
Valves are worn, burned or stuck - Clean or replace valves.
Sleeve, piston, or rings are damaged - Replace defective components as required.
Valve clearance is wrong - Need to adjust valve clearance.
| Engine using too much oil |
Seals or gaskets are defective - New components need to be installed.
Valve guides and stems are worn - Valves need to be changed.
Piston rings are defective or worn - Piston rings need to be replaced.
Cylinder liner or piston is scored - Check piston and liner, install new parts as required.
Blocked breather hose or pipe - Change or service.
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