Subaru Robin Power Products EH12-2, EH17-2, EH25-2 manual Io. Troubleshooting

IO. TROUBLESHOOTING

The following three conditionts must be fulfilledfor satisfactory engine start.

1.The cylinder filled with a proper fuel-air mixture.

2.Goodcompressioninthecylinder.

3.Good spark, properly timed, to ignite the mixture. Theenginecannotbestartedunlessthesethreeconditionsaremet.Therearealsootherfactorswhich make engine start difficult, e.. g., a heavy load on the engine when it is aboutto start at low speed, and a high back pressure due toa long exhaust pipe.

The most common causesof engine troubles are given below:

10-1STARTING DIFFICULTIES

10-1-1FUEL SYSTEM

(1) No gasoline in the fuel tank; or the fuel cock closed.

( 2 ) The carburetor is not choked sufficiently especially when the engine is cold.

(3) Water, dust or gum in the gasoline iterfering the fuel flowto the carburetor.

(4) Inferior grade gasoline or poor quality gasoline not vaporized enough to produce the correct fuel-air mixture.

( 5 ) Thecarburetorneedlevalve is heldopen by dirtor gum.Thistroublecanbedetectedasthefuel flows out of the carburetor when the engineis idling. (Overflow)

This trouble may be remedied by lightly tapping the float chamber with the grip of a screwdriver or the like.

(6)If the carburetor overflows, excessive fuel runs into the cylinder when starting the engine, making the

fuel-airmixture too rich to burn. If thishappens,removethesparkplug,andturnthestartingpulleya/"- few turns in orderto let the rich fuel-air mixture out of the spark plug hole into the atmosphere. Keep

thechokevalveopenduringthisoperation.Drythesparkplugwell,screw it intoplace,and try to start again.

10-1-2COMPRESSIONSYSTEM

If starting difficultes and loss of power are not due to the fuel system or ignition system, the followings must be checked for possible lackof compression.

Engine inside is completelydried up becauseof a long period of storage.

Loose or broken spark plug. This causes a hissing noise made by mixture gas running out of cylinder in compression stroke during cranking.

Damaged head gasket or loose cylinder head.A similar hissing noise is produced during compression stroke.

Incorrect Valve clearance

If the correct compression is not obtained even after remedying the above, disassemble the engine and check further as follows:

a) Valve stuck open due to carbon or gum on the valve stem.

b)If the piston rings are stuck on the piston, remove the piston and connecting rod from the engine. Clean or replace the parts.

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