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Overhead Cam
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EX21
7 HP


Features & Benefits:
Chain-Driven Overhead Cam > View larger image
Chain-driven Overhead Cam design offers superior power and performance with an automatic decompression system to reduce the required pulling force by 30 to 40 percent, and ensure starting on the first pull. EX engines start instantly – even at temperatures as cold as -10 degrees C – without any perceptible kickback.

Dual Ball Bearing Crankshaft Support > View larger image
Dual ball bearing crankshaft support offers maximum stability under demanding loads.

Heavy-Duty Piston Rings and a Cast-Iron Cylinder Liner > View larger image
Heavy-duty piston rings coupled with a cast-iron cylinder liner resist wear and ensure a long engine life.

Spheroidal Graphite Cast-Iron Crankshaft > View larger image
The crankshaft is made of spheroidal graphite cast iron, and the crank pin is high-frequency induction hardened. Both the crank sprocket used to drive the chain, and the gear used to drive the governor gear, are pressed on the output end of the shaft.

Pent-Roof Combustion Chamber > View larger image
Pent-roof combustion chamber enables optimum intake and exhaust valve placement for maximum engine performance and efficiency.

Case-Hardened Steel Timing Chain > View larger image
Case-hardened steel timing chain allows for precision timing and maximum durability.

Hardened Steel Rocker Arms > View larger image
Hardened steel rocker arms with precision tappet adjusters are used for greater durability and reduce service requirements.

Automotive Collets and Forged Steel Valve Retainers > View larger image
Subaru EX engines use automotive quality collet valve retainers for longer life.

Patent-Pending Connecting Rod Dipper > View larger image
The EX lubrication system begins with a patent-pending oil scoop to project the oil to the chain.

Special Cooling Fins Cast Into Block > View larger image
Cooling fins are cast into both the inside and the outside of the crankcase to utilize every possible cooling area.

Aluminum Alloy Die-Cast Connecting Rod > View larger image
The connecting rod is a specially heat-treated aluminum alloy die-casting. Its large and small ends function as bearings. A splasher built into the connecting rod lubricates by splashing engine oil. The piston is an aluminum alloy casting with grooves for mounting compression and oil rings.

Mounting Base Cooling Fins > View larger image
The unique Subaru cooling system extends to the underside of the mounting base. Air is forced over special cooling fins at the bottom of the engine for maximum cooling.

Cylinder Head 360-Degree Cooling > View larger image
Head cooling is critically important to long engine life. The Overhead Cam design allows for 360-degree air flow around both the exhaust and intake valve stem areas.

Patent-Pending Cylinder Cooling Fins > View larger image
Air is forced over the large slanted cooling fins on the cylinder for improved cooling performance. This design is patent-pending.

Patent-Pending Valve Cover Design > View larger image
A patent-pending rocker cover design constantly supplies an optimum amount of oil to the cam shaft and rocker arm even if the engine is inclined.

Patent-Pending Breather System > View larger image
A patent-pending breather system with a pre-separation
passage prevents oil from spouting even if the engine is inclined.

Hot Spark Ignition System > View larger image
The ignition system is a transistor controlled magneto with the ignition timing set at 23 degrees before top dead center. The magneto consists of a flywheel and ignition coil. To ensure the easy startability of the engine, the step advancing ignition timing system is incorporated in the ignition coil. This system enables the engine to have basically two different ignition timings according to the engine speed.

Optimized-Capacity Rigid Muffler > View larger image
Optimized-capacity rigid muffler and 33 percent fewer moving valve train parts than OHV designs, reduce mechanical noise levels a full 2 decibels below competitive models.

NO Special Tools Needed > View larger image
Even though the EX series of engines bring the latest technology, performance, and durability to the industrial air cooled engine market, there are no special tools required to work on them. Most shop tools that small engine mechanics currently own will also work on these engines for service or complete tear down. Subaru engineers achieved their commitment to 'keep it simple', while utilizing the latest technology.

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7 HP EX21
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