Briggs & Stratton 500E, 550E and 550EX, 140cc (models 09P6, 09P7, 09P8)
These are Briggs & Stratton's 140cc overhead-valve push mower engines. The model number starts with 09P. The 500E uses a primer bulb (Prime N' Pull). The 550EX uses ReadyStart, so there is no primer.
Models 09P6, 09P7, 09P8140cc OHVVertical shaft
Specs and part numbers at a glance
- Model number starts
- 09P6, 09P7 or 09P8Briggs lists the 500E as 09P8 and the 550E/550EX as 09P7. Older 140cc engines with 09P6 numbers use the same plug, filter and carburetor kit.
- Displacement
- 140 cc (8.64 cu in)
- Bore x stroke
- 2.496 in x 1.75 in
- Spark plug
- Briggs 692051
- Plug gap
- 0.020 in (0.51 mm)
- Plug torque
- 180 lb-in (20 Nm)
- Oil
- 15 oz (0.44 L), SAE 30 or 10W-30
- Air filter
- Foam element 799579Briggs lists an oiled foam filter on the 500E and E550. Some 550EX engines use a paper cartridge instead; check your parts list.
- Fuel
- Fresh unleaded, 87 octane or higher, up to E10. No E15 or E85.
- Coil (armature) air gap
- 0.006–0.014 in (0.15–0.35 mm)
Find the model number
Briggs & Stratton stamps the model, type and code into the metal of the engine, in one of three places (A, B or C on the drawing below): above the spark plug, on a plate between the valve cover and the air filter, or above the muffler. On this engine the model starts with 09P. The full number looks like 104M02-0001-F1: model, type, then trim. If you only find 9 characters, add a zero to the front. The code is the build date (year, month, day) and decides which carburetor kit fits.
Where the number is stamped
- ABriggs & Stratton: stamped into the metal just above the spark plug. You may need a flashlight.
- BBriggs & Stratton: stamped on a small metal plate between the valve cover and the air filter.
- CBriggs & Stratton: stamped on the sheet metal above the muffler, which can be on either side.
- DHonda: the model (it starts with G, like GCV170) is on a sticker on the engine. The serial number and type code are stamped into the side of the engine.
Mowers that use this engine
Toro lists this engine size on the mower below. Check the stamped number on your engine before ordering.
| Mower | Model no. | What the maker lists |
|---|---|---|
| Toro 21 in. Recycler push mower | 21311 | Toro lists a Briggs & Stratton EX 140cc engine, 5.5 ft-lb |
Parts and part numbers
Check the number against the parts list for your exact model before you order.
| Part | Part number | Notes |
|---|---|---|
| Spark plug | 692051 | Parts lists 09P702-0278-F1 and 09P602-0071-H5, ref 337 |
| Air filter, foam | 799579 | Ref 535 on 09P6, 09P7 and 09P8 parts lists |
| Carburetor overhaul kit | 594636 | Ref 121 on all three |
| Fuel line | 791766 | Ref 187 |
| Starter rope | 591108 | Ref 58 (09P6, 09P7) |
| Cylinder head gasket | 799586 | Ref 7 |
| Spark plug wrench | 19576S | Ref 383 |
Tools you need
- Spark plug socket or Briggs wrench 19576S
- Wire-type gap gauge
- Torque wrench (lb-in range)
- Screwdriver and socket set
- Oil drain pan
- Carburetor cleaner spray
- Gloves and eye protection
Maintenance and repairs, step by step
Replace the spark plug
Once a year, or sooner if the engine is hard to start.
| 01 | Pull the boot straight off the plug. Clean around the plug so dirt does not fall into the cylinder. | Engine cold. |
| 02 | Remove the plug with a spark plug socket or the Briggs plug wrench 19576S. | |
| 03 | Set the gap on the new plug to 0.020 in (0.51 mm) with a wire gauge. | |
| 04 | Thread the plug in by hand first so it can't cross-thread. | |
| 05 | Tighten to 180 lb-in (20 Nm). Push the boot on until it clicks. | Torque from the Briggs operator's manual. |
Service the air filter
Every 25 hours or once a season; more often in dust.
| 01 | Open the air filter cover. | |
| 02 | Take out the foam element. | |
| 03 | Wash it in warm soapy water, rinse it, and squeeze it dry in a clean cloth. Don't twist it. | Replace it (799579) if it is torn or crumbling. |
| 04 | Let it dry fully before you refit it. | Follow your operator's manual if it calls for oiling the foam. |
| 05 | Refit the element and close the cover. |
Change the oil
After the first 5 hours on a new engine, then every 50 hours or once a year.
| 01 | Run the engine a few minutes to warm the oil, then stop it and pull the plug boot. | |
| 02 | Drain or siphon the tank first if you can. Tip the mower onto its side with the air filter facing up, and let the oil run out of the fill tube into a pan. | Air filter up, every time. Tipping it the other way floods the filter with oil and fuel. |
| 03 | Set the mower level. Pour in about three quarters of 15 oz (0.44 L) of fresh oil, wait 3 minutes, and check the dipstick. | SAE 30 or 10W-30, API SJ or higher. |
| 04 | Add a little at a time until the oil reaches the full mark. Do not overfill. | |
| 05 | Refit the dipstick and take the old oil to a recycling point. |
Clean the float bowl and main jet
When the engine won't start or dies after fresh fuel and a new plug.
Safety Work outdoors on a cold engine. Gasoline vapor ignites easily, so no smoking, sparks or pilot lights nearby, and wipe up spills before you start the engine.
| 01 | Turn off fuel supply if your mower has a shutoff. Otherwise run the tank dry or drain it. | |
| 02 | Remove the air filter cover and filter so you can see the carburetor. | Take a photo of the linkage and springs before you touch anything. |
| 03 | Put a rag under the carburetor and remove the bowl screw. Lower the float bowl off. | The bowl gasket is listed in your parts list. |
| 04 | Spray carburetor cleaner through the main jet and the bowl screw passage. Clean out any varnish or water in the bowl. | Never push wire through the jet; it enlarges the hole. |
| 05 | Check that the float moves freely and the needle is clean. | If parts are worn or the gasket is hard, fit the overhaul kit 594636. |
| 06 | Refit the bowl with the gasket seated, then the filter. Refill with fresh fuel and test. | Do not bend the governor linkage or move the governor spring. |
Troubleshooting by symptom
| Symptom | Likely cause | What to do |
|---|---|---|
| Engine won't start (500E) | Primer not pressed, or primer bulb cracked | Press the primer 3 times firmly before pulling. Replace a cracked bulb. |
| Won't start after storage | Stale fuel in the tank and carburetor | Drain the tank, refill with fresh fuel. If it still won't start, clean the float bowl (see the carburetor job). |
| Starts, then dies | Varnish in the carburetor main jet, or a blocked fuel cap vent | Clean the float bowl and main jet. If it only runs with the fuel cap loosened, replace the cap. |
| Hard to pull, then won't turn | Blade hitting grass or debris, or a bent blade | Disconnect the plug wire, tip the mower air filter side up, clear the deck and check the blade. |
| Surges or hunts at full speed | Dirty air filter or a partly blocked jet | Replace the filter, then clean the carburetor. Do not adjust the governor spring or linkage. |
| Blue or white smoke | Mower was tipped the wrong way, or oil overfilled | Check the dipstick. Always tip a Briggs push mower with the air filter side up. |
| No spark | Fouled plug or wrong coil air gap | Fit a new plug at the correct gap. Check the coil air gap with a gauge card. |
Owner's manuals and parts lookups
These go to the maker's own sites.
- Briggs & Stratton manual and parts list lookup Enter the full model-type-trim number
- Briggs & Stratton: where to find the model number Push mower engines
- Briggs & Stratton model numbering key (PDF) What each digit means
- Briggs & Stratton E series specifications E450 and E550
Something wrong or missing?
Tell us the full model number on your engine and what you found.