Briggs & Stratton 21R707-0145-G1 engine Parts

The Briggs 21R707-0145-G1 is the engine model itself; it identifies a specific Briggs single-cylinder, vertical-shaft lawn and garden engine configuration. When ordering parts or confirming fit, match the full model number exactly and use the parts list for 21R707-0145-G1.

How to confirm you have the right engine model

We recommend verifying the engine’s model-type-code stamping on the blower housing or valve cover area (location varies by shroud style). The stamping should include 21R707 plus additional numbers/letters.

• Clean the stamping area so all characters are readable
• Match the full string (model, type, and code) before ordering parts
• If the equipment has its own model number, do not use that for engine parts
• Use the engine model to select tune-up and fuel system parts

Common parts customers replace on this engine

If you are servicing a no-start, surging, or power-loss issue on a 21R707-0145-G1, these are common maintenance and repair items found for this model:

• Briggs & stratton lawn & garden equipment engine fuel filter (white) 394358S
• Briggs & stratton lawn & garden equipment engine air filter 591583
• Briggs & statton lawn & garden equipment engine carburetor rebuild kit 796184
• Briggs & statton lawn & garden equipment engine ignition coil 594626

Quick symptom-to-part check

Symptom	Most common checks	Parts on this model page
Starts then dies	Fuel flow restriction, dirty carburetor	Fuel filter, carburetor rebuild kit
Surges at idle	Lean condition, varnished jets	Carburetor rebuild kit
No spark	Coil/boot/wiring issue	Ignition coil, spark plug boot
Cranks slowly or not at all	Starter or battery/cables (equipment side)	Starter motor

Why it matters

Briggs engine families can look similar, but internal and external parts (carburetor, ignition, gaskets, seals) change by model and type. Using the exact 21R707-0145-G1 identification prevents wrong-part returns and speeds up repairs. You can order replacement parts from the parts list for this model, or search by model number on Sears PartsDirect.

Last updated: February 2026

On the Briggs 21R707-0145-G1 lawn and garden engine, valve clearance (valve lash) is set with the engine cold and the piston at top dead center on the compression stroke. For this model, a reliable cold starting target is 0.003 in. intake and 0.005 in. exhaust.

Valve clearance specs (cold)

Set lash with a feeler gauge so it has a slight, smooth drag.

Valve	Clearance (cold)	Where you measure
Intake	0.003 in.	Between rocker arm and valve stem tip
Exhaust	0.005 in.	Between rocker arm and valve stem tip

How to set valve clearance on the 21R707-0145-G1

• Remove the spark plug boot so the engine cannot start.
• Remove the valve cover.
• Rotate the crankshaft to TDC on the compression stroke (both valves closed).
• Insert the correct feeler gauge at the rocker arm to valve stem contact point.
• Loosen the rocker nut, adjust to the clearance, then tighten and recheck.
• Rotate the engine two full revolutions, return to TDC compression, and recheck.

Parts that commonly affect results after a valve adjustment

If it still starts hard, surges, or lacks power, these tune-up items often matter:

• Replace a restricted fuel filter: Briggs & stratton lawn & garden equipment engine fuel filter (white) 394358S
• Replace a dirty air filter: Briggs & stratton lawn & garden equipment engine air filter 591583
• If cranking is slow, test the starter circuit and consider: Briggs & stratton lawn & garden equipment engine starter motor 593934

Why it matters

Correct valve lash keeps compression and valve timing where they belong. Tight valves cause hard starting (especially hot) and low power; loose valves increase noise and can reduce performance.

You can order replacement parts for your 21R707-0145-G1 from the parts list for this model, or search by model number on Sears PartsDirect.

Last updated: February 2026

For the Briggs 21R707-0145-G1 lawn and garden engine, use a high-quality 4-cycle engine oil; SAE 30 is a strong choice for warm-weather mowing, and 10W-30 works well when temperatures swing. Add oil by dipstick level (not by a fixed ounce amount) to avoid overfilling.

Recommended oil viscosity (SAE grade)

Choose viscosity based on the temperatures you run the engine in:

• SAE 30: best for consistently warm conditions
• 10W-30: best for variable spring and fall temperatures
• 5W-30 synthetic: best for colder starts and easier cranking
• API service rating: use a modern detergent oil intended for 4-stroke engines

How to fill correctly (best practice)

Oil capacity varies by exact crankcase and dipstick configuration, so the correct method is to fill to the mark.

• Park the equipment on level ground
• Let the engine cool, then remove the dipstick
• Add oil slowly, pausing to let it settle
• Recheck the dipstick and stop at the FULL mark
• Run the engine briefly, shut it off, then recheck and top off if needed

Quick reference table

Outdoor temperature	Oil to use	What you get
Above ~40°F	SAE 30	Stable protection in heat
~0°F to 100°F	10W-30	Better across temperature changes
Below ~40°F	5W-30 synthetic	Faster lubrication at startup

Why it matters

Correct viscosity and correct fill level protect internal parts from wear and overheating. Overfilling can cause smoking, fouled plugs, and leaks; underfilling can quickly damage the engine.

Parts that often go with an oil service

If you are doing a tune-up at the same time, these model-matched parts are commonly replaced:

• Briggs & stratton lawn & garden equipment engine air filter 591583
• Briggs & stratton lawn & garden equipment engine fuel filter (white) 394358S

You can order replacement parts for your Briggs 21R707-0145-G1 from the parts list for this model, or search by model number on Sears PartsDirect.

Last updated: February 2026