Spark plug gap - 0.030 of an inch.

Use a new spark plug at the beginning of a new season. Replacement plug must be of the correct heat range, like Champion No. D-16J, AC No. C86 commercial or equal. Thread size is 18mm.

Use a new gasket when mounting either old or new plug and thoroughly clean threads in cylinder head before installation. Tighten spark plug 28 to 30 foot pounds torque. If torque wrench is 'not available, tighten plug until it begins to seat on the gasket, then turn 1/2 to 3/4 of a turn more.

CLUTCH AND REDUCTION GEARS

CLUTCH TAKE-OFF (Fig. 17)
The clutch in the take-off assembly, available on this model of engine, is of the multiple disc type running in oil. Use the same grade of oil in clutch housing as is used in the engine crankcase, and fill to the height of the oil level plug, through the inspection plate opening; about I print of oil is required.

Reduction gears are furnished in several different ratios, some with spur gears, others with chains. All are of the same general design, except that some are furnished with clutches, others without.

Use some grade oil as used in engine crankcase.

Several plugs are furnished so that lubrication may be properly taken care of regardless of the position of installation. There will always be one plug on top to be used for filling oil, one plug below for draining oil, and a plug on the side, slightly above bottom, for the oil level. The oil should always be filled when the engine is at rest. When oil becomes dirty it should be drained while the engine is hot, and fresh oil added. The frequency at which these oil changes should be made depends entirely on the kind of service in which these gears are used, but even with light service;

Fig. 18

Drain crankcase oil while engine is warm.

Drain fuel lines, carburetor, fuel pump and tank, to prevent lead and gum sediment from interfering with future operation. Gasoline fumes from gradual evaporation is a dangerous fire hazard.

The air cleaner and filter element should be thoroughly cleaned. Tape or otherwise seal off the exhaust and air cleaner openings for the duration of the storage period.

The outside of the engine, including the cooling fins on the cylinder and head, should be thoroughly cleaned of all dirt and other deposits. All exposed unpainted metal parts should be coated with grease or heavy oil.

Before adding new crankcase oil the next season, drain base of condensation which may have accumulated during the storage period.

On take-off units, the lock' screw is accessible thru the pipe plug hole behind the inspection opening.

Keep clutch from turning by holding rope starter sheave firmly in place with the left hand. Then, by means of a screw driver, turn adjusting ring one notch at a time in a clockwise direction, until a definite pressure is felt on the clutch lever when engaging. When properly adjusted, the clutch will engage with a slight snap. Tighten lockscrew and mount inspection cover. Be sure cover gasket is in good condition.

RESTORING COMPRESSION
On a new engine, or one which has been out of opera. tion for some time, the oil may have drained off the cylinder so that compression will be weak. This may cause difficulty in starting. To remedy this condition, remove the spark plug and pour about a fluid ounce of crankcase oil through the spark plug hole. Turn engine over several times with the rope starter to distribute oil over the cylinder walls. Then mount spark plug an, compression should be satisfactory.

WINTER STORAGE
To protect the cylinder, piston, rings, valves, and keep them from rusting and sticking, a half and half mixture of kerosene and good engine oil, (the same kind of oil as used in the crankcase of the engine), should be injected into the pipe tap opening on the air cleaner bracket while the engine is warm and running at moderate speed. About a quarter of a pint is necessary, or enough so that a heavy bluish smoke will appear at the exhaust. The ignition switch should then be shut off and the engine stopped. This fogging operation will leave a coating of oil on the above mentioned parts, protecting them from the atmosphere. Aft&,: the engine has stopped, disconnect the spark plug cable and turn engine over slowly until the flywheel key or take-off shaft keyway is up, or in the 12 o'clock position and on compression stroke. Both valves will then be closed and the piston will be on top in the cylinder bore. This will minimize rusting of the cylinder bore and help in retaining the oil fog previously injected into the engine.

Fill crankcase with a good quality of oil to the high level point, before starting engine. Do not use any oil heavier than S.A.E. No. 30.

Use a new spark plug at the beginning of the next season, especially if the engine has given considerable service.

It is highly recommended that machines be stored inside a building through the winter.

If this is not possible, the engine should be protected from snow and ice by a proper covering.

TROUBLES CAUSES AND REMEDIES
Three prime requisites are essential to starting and maintaining satisfactory operation of gasoline engines. They are:

1. A proper fuel mixture in the cylinder.
2. Good compression in the cylinder.
3. Good spark, properly timed, to ignite the mixture.

If all three of these conditions do not exist the engine cannot be started. There are other factors which contribute to hard starting; such as too heavy a load for the engine to turn over at low starting speed, a long exhaust pipe with high back pressure, etc. These conditions may affect starting, but do not necessarily mean the engine is improperly adjusted.

As a guide to locating any difficulties which might arise the following causes are listed under the three headings: Fuel Mixture, Compression, and Ignition. In each case the causes of trouble are given in the order in which they are most apt to occur.

STARTING DIFFICULTIES

FUEL MIXTURE
No fuel in tank or fuel shut-off valve closed.