Subaru Robin Power Products EY15V, EY20V Pilotsystem, Disassembly and Reassembly, Throttle System

Page 38

8- 1- 2 PILOTSYSTEM

The pilot system feeds the fuel to theengine during idling and low-speed operation.

The fuel is fed through the main jet to the pilot jet,where it is metered, and mixed with the air metered by the pilot air jet.

The fuel-air mixture is fed to theengine through the pilot outlet and theby-pass. During engine idling, the fuel is mainly fed from the pilot outlet.

8- 1 - 3 MAIN SYSTEM

The main system feeds the fuel to theengine during medium- and high-speed operation.

The fuel is metered by the main jet and fedto the main nozzle. The air metered by the main air jet is mixed with the fuel through the bleed holes in the main nozzle, and the mixture is atomized out of the main bore. It is mixed again with the air taken through the air cleaner into an optimum fuel-air mixture, which is s u p plied to theengine.

8 - 1 - 4 CHOKE

The choke is used for easy start in the'cold season. When the recoil starter is pulled with a closed choke, the negative pressure applied to the main nozzle increases and draws much fuel accordingly; thus easily start up the engine.

8-2 DISASSEMBLY and REASSEMBLY

Apart from mechanical failusres, most of carburetor troubles are caused by an incorrect mixing ratio, which may arise mainly due t o a clogged up air or fuel passage in jets, or fuellevel variations. In order to assure pro- per flow of air and fuel, the carburetor must be kept clean at all times. The carburetor disassembly and re- assembly procedures are as follows: (See Fig.5 1.)

8-2- 1 THROTTLE SYSTEM

1)Remove the Philips screw (33) and throttle valve

(28), and pull out the throttle shaft(29).

2 ) The spring (30)can be takenoutby removing the throttle stopscrew (3 1).

*Exercise care not to damage throttlevalve ends.

8 - 2 - 2 CHOKE SYSTEM

1) Remove the Philipsscrew (22)andchoke valve (23), and pull out the choke shaft(24).

2) When reassembling thechokeshaft,make sure

17

 

that the cutoutin the chokevalve faces the main

 

air jet.

 

Meantime, when reassembling set the rings (26)

 

and (27) at the right position.

 

8-2-3 PILOT SYSTEM

 

1) Remove the pilotjet (32), using correct tool to

 

avoid damage to it.

 

2) Reassembly

 

Tighten the pilotjet securely. Otherwise,the fuel

 

may leak, causing engine malfunction.

Fig. 51

 

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Contents Page Side Valve Wisconsin RobinContents Basic Theory ofT .I.C SPEC1FICATIONS ModelPerformance Continuous Rated OutputFeatures CYLINDER,CRANKCASE Crankshaft6VALVEARRANGEMENT Connecting ROD and PistonCamshaft Lubrication CylinderheadCooling 111IGNITION 112CARBURETORSectional View of Engine Model EY15VAir Cleaner Muffler Cover Model EY20V Model EY20V Preparations and Suggestions Special ToolsApplicalbeShape Model 3HOW to Disassemble OrderTool Order Exhaust valve Main bearing cover Procedures Remarks OrderProcedures MOW to Reassemble Precaution in reassembling~Sequesnceand precautionsin reassembling CrankshaftDimensions of Crankshaft Pin EY15V EyzovPeriphery.I Y20 5 Mainbearing Cover 6INTAKE and Exhaust Valves Valve and Valve Guide Clearance7TAPPET Adjustment ’ 5-4-8CYLINDER Head Kg-cm1FUEL Tank Bracket Intake Manifold14AIRCLEANER 1 7 Recoil StarterMagneto BreakerpointadjustmentTo 6-3TIMING Adjustment MagnetoTiming Adjustment See Figs ,43 Solidstate Ignition MagnetotroubleshootingSpark Testing C. Transistorignitioncircuit Discrimination accordingto the dimensions Governoradjustment Point where the governorspring is to be hooked Page Carburetor 1 Float System1 Throttle System Disassembly and Reassembly2 Pilotsystem Float System BREAK-IN Operation of Reassembledengine Basic Theory of T.I.C. See Fig FeaturesIO. Robin Solid State Ignition Engine 11- 1 Starting Difficulties 11- 1-2 Compression System11-3ENGINE Stops 11- 1-3ELECTRICAL System11-2ENGINGEMIFIRES 11- 4 Engine OverheatsEngineknocks Enginebackfires through CarburetorVENT1LATION InstallationPower Transmission to Drivenmachines Exhaust GasdischargeSolid State Ignition Type WiringBreaker Point Ignition Type Checks and Corrections Table of Correctionstandards 1.o 10*0.02 #20 220 15-3EVERY 50 Hours IO Dayschecks and Maintenance Daily Checks and MaintenanceEvery 20 Hours Checks and Maintenance Every 100 200 Hours Monthly Checks and MaintenancePREPARATiON for Longabeyance Every 500 600 Hours Semiannual Checks and MaintenanceEvery 1000 Hours Yearly Checks and Maintenance Page Page Page Page Industrial Engines
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