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Overhead Cam
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EX21 Fuel Injection
7 HP


Features & Benefits:
Air Cleaner Removed > View larger image
This view shows the air cleaner removed and the throttle body's main components.

Cutaway View of Throttle Body > View larger image
This cutaway view of the single piece throttle body gives a description of some of the components and connections.

Cutaway View of Throttle Body > View larger image
This view shows the Delphi Injector in the cavity of the throttle body. This injector is easily serviced.

EX21 With Components Removed > View larger image
In this picture, the flywheel, air cleaner, recoil, throttle body and gas tank are removed to show the main components of fuel injection, power coil and wiring harness.

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.

Cast-Iron Cylinder Liner > View larger image
Cast-iron cylinder liners enhance reliability and extend engine life.The cast iron cylinder liner has much better wear characteristics than the softer aluminum that surrounds it, making engine life much longer than if the piston is in contact with the aluminum cylinder wall.

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.

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

Camshaft with Automatic Decompression Release > View larger image
The camshaft and the sprocket are made of special sintered alloy and constructed as a single piece. The camshaft is provided with intake and exhaust cam in one cam lobe. The decompression release lever is mounted on the sprocket end side.

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

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

High Efficiency Intake Port > View larger image
The illustration shows the straight intake port on the right side of the picture. The lower resistance to the flow of the air/fuel mixture improves the power, efficiency and lowers emissions. Overhead Cam (OHC) technology allows the intake and exhaust valves to be positioned for optimum performance.

High Power Pent-Roof Design > View larger image
Overhead Cam (OHC) technology and the Pent-Roof combustion chamber allow the Subaru EX engines to use a higher compression ratio of 9:1. The higher compression ratio increases the power produced for a given size engine. It also improves efficiency and overall performance.

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.

Intake Valve Seal > View larger image
Special machining on cylinder head allows the oil seal to be placed around the valve guide. This seal reduces oil consumption and is replaceable for service.

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.

Optimized Capacity-Rigid Type 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.

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

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.

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 valve cover design constantly supplies an optimum amount of oil to the cam shaft and rocker arm even if the engine is inclined.

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

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. The crank sprocket used to drive the chain, as well as the gear used to drive the governor gear, are pressed on the output end of the shaft.

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 this engine. Most shop tools that small engine mechanics currently own, will also work on this engine for service or complete tear down. The commitment by the Subaru engineers to 'keep it simple', but use the latest technology was achieved.

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7 HP EX21 Fuel Injection

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