Briggs & Stratton Intek Ohc Model 21 Series. 21R877-0015

Intek Ohc Model 21 Series. - 21R877-0015 - Briggs & Stratton

The Briggs & Stratton 3130 Intek OHV is a 344cc, 13HP single-cylinder petrol engine for ride-on mowers and lawn tractors. At 9.9kW gross and 22.75Nm of torque at 3600rpm, the output figures are the same as the standard 3130 PowerBuilt — but this variant is a step up in specification. It comes with both recoil and electric start, full pressure lubrication, a spin-on oil filter and a muffler included as standard. For anyone replacing an engine on a mid-range tractor where those features were present on the original, this is the like-for-like choice rather than the base model.

Dual Start — Recoil and Electric

Unlike the electric-only variants in this series, this engine has both starting options. The electric start handles day-to-day use, while the recoil provides a reliable fallback if the battery is flat or the machine has been laid up for a period. On a machine that may sit unused over winter, having both available is genuinely worth having rather than a redundant feature.

Pressure Lubrication with Spin-On Oil Filter

Oil is circulated under pressure to the crankshaft bearings and other load-bearing components, rather than relying on splash contact. The spin-on oil filter works alongside this to trap metallic particles and combustion byproducts before they recirculate through the engine. Together these two features are what separate this engine from the splash-lubricated Intek variants — internal components stay cleaner, wear rates are lower, and the engine tolerates sustained use on uneven ground far better than a splash-lubricated unit where the oil level constantly shifts.

OHV with Cast-Iron Cylinder Sleeve

The 3130 Intek uses Briggs & Stratton's Dura-Bore cast-iron cylinder sleeve throughout. The overhead valve layout keeps combustion temperatures manageable during extended running, and the cast-iron bore maintains its geometry under heat and load in a way that an aluminium bore cannot over the same period. This combination underpins the engine's long service life in regular seasonal use.

ReadyStart™ Automatic Choke

The carburettor choke is managed automatically by the ReadyStart system, which reads engine temperature and adjusts the fuel mixture without any manual input from the operator. No priming, no choke lever — the engine starts the same way whether it is cold or already warmed up, operating reliably between 0°C and 49°C.

AVS® Anti-Vibration System

Briggs & Stratton's AVS linear balancing system reduces the power pulse vibration that is inherent in single-cylinder engines. On a ride-on machine covering larger areas in a single session, the difference in operator comfort is noticeable, and the reduction in chassis fatigue over a machine's lifetime is a practical benefit rather than simply a comfort feature.

9-Amp Charging System & Fuel Pump

The 9-amp alternator supports the battery and any 12V accessories the host machine runs — electric PTO clutches, lights or dashboard electronics. The mechanical fuel pump draws from the machine's remote tank, which is the standard configuration on virtually all ride-on mowers and lawn tractors.

Muffler Included

A muffler is supplied fitted to the engine. This is worth confirming for anyone replacing an existing engine, as many bare replacement engines are sold without one.

Fitment & Compatibility

The vertical crankshaft is 25.4mm (1 inch) in diameter and 80.19mm (3 5/32 inches) in length with a keyway — a configuration used widely across ride-on mower and tractor platforms. No fuel tank is included; kit B995020 is available separately if required. If you need to confirm suitability before ordering, contact us with your original engine's model, type, and code numbers and our staff will advise.

Specifications

Series: 3130 Intek OHV

Cylinders: Single, Cast-Iron Sleeved

Displacement: 344cc

Power Output: 13HP / 9.9kW Gross (22.75Nm @ 3600rpm)

Fuel Type: Petrol

Cooling: Air-Cooled

Crankshaft: Vertical, 1" (25.4mm) diameter x 3 5/32" (80.19mm) length, Keyway

Flywheel: Heavy

Top No-Load RPM: 3200 ±100

Charging System: 9 Amp

Choke: ReadyStart (Automatic)

Electric Start: Yes

Recoil Start: Yes

AVS Anti-Vibration: Yes

Lubrication: Full Pressure

Oil Filter: Yes (spin-on)

Fuel Pump: Yes

Low Oil Cut-Off: No

Muffler: Yes (included)

Fuel Tank: No

Oil Capacity: 1.42 litres (approx.)

Power and torque figures stated gross per SAE J1940 as rated by Briggs & Stratton.

Always read the owner's manual before commissioning. Damage resulting from improper installation is not covered under warranty. Shipping restrictions may apply outside of the UK — please contact us to confirm.