G333 & 3306 NATURAL GAS ENGINES Lubrication And Maintenance Procedures Caterpillar

Lubrication And Maintenance Procedures
1.1. Engine Lubrication System
2.2. Checking Oil Pressure
3.2. Checking Oil Level
4.2. Draining Crankcase Lube Oil
5.2. Cleaning Breather
6.2. Changing Filter Elements
7.2. Filling Crankcase
8.1. Air Induction And Exhaust System
9.2. Single Stage Air Cleaner
10.2. Cleaning Filter Elements
11.2. Valve Lash
12.2. Valve Rotators
13.2. Exhaust Bypass Valve Breather (Turbocharged Engine Only)
14.1. Cooling System
15.2. Checking Water Temperature Reading
16.2. Checking Coolant Level
17.2. Draining Radiator or Expansion Tank
18.2. Draining Engine Jacket Water
19.2. Cleaning Cooling System
20.2. Filling Cooling System
21.2. Fan - Alternator Belts
22.1. Starting System
23.2. Air Starting
24.1. Electrical System
25.2. Battery
26.2. Maintaining The Battery
27.2. Mechanical And Solid State Magnetos
28.2. Spark Plugs
29.1. Power Coupling System
30.2. Flywheel And/Or Front Power Take-Off Clutches
31.2. Electric Set Generator
32.1. Miscellaneous Maintenance
33.2. Tachometer Drive
34.2. Shut Off

Engine Lubrication System

Checking Oil Pressure

Immediately after starting and frequently during operation, observe the oil pressure gauge. If the gauge indicator registers below "NORMAL", or if the indicator fluctuates, check the oil level and take corrective measures.

Checking Oil Level

Check the oil level with the engine idling. Oil level must be between the ADD and FULL marks on the dipstick. Add oil as required.

Draining Crankcase Lube Oil

With engine stopped and oil warm:

1. Wipe dirt from each oil filter housing.

2. Remove the oil filter housing drain plug.

3. Remove the crankcase oil plug.

4. Allow oil to drain. Clean and install drain plug.

Cleaning Breather

1. Release the hose clamp and disconnect the fumes disposal tube.

2. Remove the breather assembly.

3. Inspect the gasket. Replace if necessary.

4. Wash the breather and elements in clean solvent.
5. Install the breather and fumes disposal tube.

Changing Filter Elements

1. Drain the filter housing.
2. Loosen the filter housing mounting bolt.

3. Remove housing and element.

4. Remove element from housing.

5. Wipe filter base.

6. Clean filter housing.

7. Inspect gasket in filter base. Replace gasket if necessary.

8. Install new element and housing.
9. Install filter drain plug.

Filling Crankcase

1. Fill the crankcase to the SAFE STARTING RANGE on the ENGINE STOPPED side of dipstick. See the Lubrication and Maintenance Chart for refill capacity and proper oil to use.
2. Check oil level before starting.

3. Start and run engine. Check for oil leaks.
4. After engine is warm, check oil level with engine idling. Add oil if necessary.

Air Induction And Exhaust System

Single Stage Air Cleaner

Changing Filter Element


Service the air cleaner with the engine STOPPED.

1. Remove cover (1).
2. Remove wing bolt (2); inspect the gasket. Replace the bolt assembly if the gasket needs replacing.

3. Remove filter element (3). Cover the air inlet opening (4) to prevent dirt from entering the engine.
4. Clean the inside of the air cleaner cover, and the air cleaner body.
5. Inspect the replacement element for damage and dirt.
6. Remove the covering from the air inlet opening.
7. Install the element. Tighten the wing bolt securely. Install the air cleaner cover.

See the instructions for air cleaner element cleaning.

Changing Filter Element [Heavy Duty]


Service the air cleaner with the engine STOPPED.

1. Remove the air cleaner cover and element.

2. Cover the air inlet opening to prevent dirt from entering the engine.
3. Clean the inside of the air cleaner cover and the air cleaner body.

4. Inspect the replacement element for damage and dirt.
5. Remove the covering from the air inlet opening.
6. Install the element.

7. Install the air cleaner cover.

Cleaning Filter Elements

Cleaning Elements With Air

------ WARNING! ------

When using pressure air, wear protective face shield and clothing. Use 30 psi (205 kPa) maximum pressure air for cleaning purposes.

1. Use clean, dry air - 30 psi (205 kPa) maximum. Hold the nozzle at least one inch from the element and at a slight angle. (A direct blast can rip the pleating.)

2. Direct the air stream along the complete length of each pleat on the CLEANEST side of the element. (This will loosen the dirt from the dirtier side.)
3. Blow the loosened dirt from the DIRTY side.
4. Direct the air from the CLEAN side through to the DIRTY side to remove dirt blown into the pleating.

Cleaning Elements With Water
1. Use clean water at no more than 40 psi (280 kPa) maximum. Do not use a nozzle.
2. Direct the water stream along the complete length of each pleat on the CLEAN side of the element.

3. Direct water along the complete length of each pleat on the DIRTY side of the element.
4. Rinse the CLEAN side of the element.
5. Allow the cleaned element to dry thoroughly.

Cleaning Elements With Detergent
1. Wash both sides of the element in a solution of warm water and non-sudsing household detergent.
2. Rinse the cleanest side of the element with clean water, 40 psi (280 kPa) maximum, along the complete length of each pleat.

3. Rinse the opposite side of the element along the complete length of each pleat.
4. Rinse the first side again to remove all loosened dirt.
5. Allow the cleaned element to dry thoroughly.

Inspecting Clean Elements
1. Hold the dried element in front of a lighted electric bulb. Carefully inspect the element for tiny, pinpoints of light. Any light showing indicates a pleat is torn. Discard the element.

2. Wrap usable elements in heavy paper.
3. Store the wrapped element in a dry, clean place.

Valve Lash

Checking Valve Lash
1. Stop the engine.
2. Wipe the base of the valve cover to keep dirt from getting into the valve mechanism.

3. Remove the valve cover.

4. Remove the flywheel housing timing cover.

5. Bar the flywheel in the direction of normal rotation.
6. Align the "TC-1" timing mark with the flywheel housing timing pointer.

7. Check the No. 1 cylinder rockers for movement. Determine if the piston is on COMPRESSION or EXHAUST STROKE.

NOTE: When on compression stroke both inlet and exhaust valve rockers can be easily moved with finger pressure.

When on exhaust stroke only the inlet valve rockers can be moved freely with finger pressure.


8. Refer to the tables below, and set only those valves specified in the appropriate table:

9. Bar the flywheel one revolution in the direction of normal rotation and align the flywheel "TC-1" timing mark.
10. Check the movement of the rockers for cylinder No. 2.

11. Set the remaining valves as specified in the remaining table.

Adjusting Valve Lash

When adjusting valve lash, engine must be stopped and cold.

1. Loosen the locknut on the adjusting screw.

2. Turn the adjusting screw to obtain the proper lash.

3. Hold the adjusting screw and tighten the locknut.

4. Recheck the lash.

Valve Rotators

Checking Valve Rotation

After checking all valve clearances, and before installing the valve cover:

1. Start the engine.
2. Move the governor control to low idle position.
3. Watch the serrations on each valve retainer. Each valve retainer should turn slightly each time the valve closes.

If a valve fails to rotate, call your AVSpare dealer.

If all valves rotate, proceed as follows:

4. Stop the engine.
5. Inspect valve cover gasket. Install new gasket if necessary.

6. Install the valve cover.
7. Install the flywheel housing timing cover.

Exhaust Bypass Valve Breather (Turbocharged Engine Only)

Remove the exhaust bypass valve breather and wash it in clean solvent.

Cooling System

Checking Water Temperature Reading

The water temperature gauge should normally register in the NORMAL range when operating. However, with some systems, as long as the coolant does not boil the cooling system is functioning properly.

1. If the water temperature gauge continually registers near - or in the "HOT" range - without boiling, have the system checked to determine if the cooling system is functioning properly.
2. Frequently check the water temperature gauge during operation. Note any deviation from the normal reading.
3. If reading is not in the NORMAL OPERATING RANGE stop the engine and have the engine serviced.

Checking Coolant Level

With the engine stopped:

1. Slowly turn the filler cap to the first stop and release pressure.

------ WARNING! ------

Be careful. If the engine is warm - steam may spray outward under high pressure.


2. Push the cap down; turn until the cap is released.

3. Maintain level to base of fill pipe.

4. Make-up coolant should be one of the following, in the order of preference:
a. Permanent anti-freeze and fresh water solution.
b. Drinkable water and rust inhibitor solution.
c. Drinkable water.
d. Any available fresh water.

(a) Must be used if engine is to be shut down in below freezing weather without draining the coolant. (b) Can only be used when the coolant temperature is above freezing, or if the coolant will be immediately drained after shut down during below freezing temperatures.

(c) or (d) Should only be used as a "temporary fix". As soon as possible, return the system to either (a) or (b).

Draining Radiator or Expansion Tank

Whenever it is necessary to drain the cooling system for repairs:

1. Shut the engine off.
2. Slowly turn the pressure cap until the cap is released.

------ WARNING! ------

Be careful. If the engine is warm - steam may spray outward under high pressure.

3. Open the drain valve on the radiator.

Draining Engine Jacket Water

1. Drain the radiator.
2. Remove the engine block drain plug.

Cleaning Cooling System

To clean the cooling system, any good commercial radiator cleaning solution can be used. Follow the instructions included with the cleaner.

The cooling system can be cleaned using oxalic acid and sodium carbonate as follows:

1. Fill the cooling system with a solution consisting of two pounds of oxalic acid or sodium bisulphate (NaHSO4) with every 10 gallons of water (mix 0,24 kg with every 10 liters of water).
2. Start the engine and operate at operating temperatures for 1/2 to 1 hour.
3. Stop the engine and drain the cooling system.
4. Flush the system with clean water until the draining water is clear.
5. Install all drain plugs.
6. Fill with a solution consisting of 1/2 pound of sodium carbonate crystals (Na2CO3) with every 10 gallons of water (mix 0,06 kg with every 10 liters of water).
7. Start and run the engine for 10 minutes.
8. Stop the engine and drain the cooling system.
9. Flush the cooling system with clean water.
10. Install all drain plugs.

Filling Cooling System

Before placing the engine in operation, make sure a 3% concentration of AVSpare Cooling System Inhibitor or equivalent hast been added to the cooling system. This 3% concentration must be maintained in cooling systems which are filled with water and systems protectected with ethylene glycol antifreeze mixture, regardless of antifreeze concentration.

Every 3 months or 500 Service Hours, whichever occurs first, add corrosion inhibitor to maintain the recommended 3% concentration.

Refer to the application chart on the container for initial fill and maintenance fill amounts.


Do not use AVSpare Cooling System Inhibitor with Dowtherm 209.

1. Use water that is low in scale forming minerals. Do not use softened water.
2. While filling the cooling system, stop the filling procedure several times to allow the coolant level to stabilize and expel air from the system.
3. Add coolant until the coolant level reaches the base of the fill pipe. Allow space for coolant expansion.
4. Start the engine and allow it to idle several minutes with the filler cap off. Add coolant as necessary.
5. Install the filler cap. Check the system for leaks.

Fan - Alternator Belts

Checking Belt Condition
1. Check belts for excessive wear, fraying and cracking.

NOTE: When belt replacement is necessary, belts must be replaced in complete matched sets. Never replace only one belt. The new belt will carry all the load and fail rapidly.

2. Apply a 25 pound (10 kg) force perpendicular to the belt, midway between the driver and driven pulley. Measure the belt deflection.

Proper belt deflection is 9/16 to 13/16" (14 to 20 mm). Adjust the belt tension as required.

Adjusting Belts
1. Loosen the anchor bolt in the slotted bracket.

2. Loosen nut (white arrow) if belt is to be tightened; loosen nut (black arrow) if belt is to be removed.

3. Tighten the opposing nut until proper belt tension is attained; or until belt is loosened.
4. Tighten the anchor bolt after belt is properly adjusted.

Lubricating Fan Drive

Lubricate the fan drive bearing with grease; 1 or 2 strokes, 1 fitting.

Starting System

Air Starting

Filling Motor Oiler

The motor oiler lubricates the vanes of the starting motor with a fine oil mist as the motor is operating.

When the oiler jar becomes half empty, remove the oil filler plug and fill the jar with clean oil. Refer to Lubrication and Maintenance Chart for proper oil.


Never allow the jar to become empty. The starting motor will be damaged by lack of proper lubrication.

Emptying Oil Collector Jar

The collector jar collects both the oil after it has lubricated the starting motor vanes and the moisture condensation from the compressed air.

Empty the collector jar whenever the jar becomes half full.

Adjusting Oiler Feed

If necessary, adjust the oiler to release approximately four drops of oil per minute into the starting motor air stream.

1. Move the compression release lever to the START position, and move the governor control lever to the SHUT-OFF position.
2. Pull up on the air start control lever and crank the engine.
3. Count the drops of oil released per minute into the air stream.
a. Turn the valve needle (the uppermost knob on the oiler) counterclockwise to increase the number of drops.
b. Turn the valve needle clockwise to decrease the number of drops.

Electrical System


Installing Battery
1. Be sure the tray is free of objects which may puncture the battery case when the hold down straps are tightened.
2. Be sure terminal posts and cable clamps are clean.
3. Place the battery in the tray. Tighten the hold down clamps evenly until the battery is snug. Do not overtighten.
4. Connect the "hot" terminal first.
5. Connect the ground terminal last.


Always connect the "hot" terminal first.

When the "hot" terminal is connected first, arcing cannot occur if the wrench accidentally contacts both the terminal and the frame or tray. The part contacted will take the same polarity as the battery terminal, whether connecting the "hot" terminal or the ground terminal.

If the ground terminal is connected first, the frame or tray is connected to ground. Then, if the wrench should accidentally contact the frame or tray while connecting the "hot" terminal, a circuit is completed from the "hot" terminal through the wrench to ground. The hot spark which will occur may burn the person holding the wrench, may weld the wrench to the metal, and may explode the battery if an excess of hydrogen gas is present at any one of the vent holes.

After connecting both cables, apply a thin coating of grease over the cable clamps, terminals and hold down fasteners.

Maintaining The Battery

Checking Electrolyte Level

Check the electrolyte level of each cell and the general condition of the battery.

1. Maintain the electrolyte level to the base of each vent well.

A proper charge rate should require periodic additions of water. No more than one ounce (30cc) of water per cell per week should be required to maintain a fully charged battery.

An overcharge condition creates heat which boils excessive amounts of electrolyte solution. Water must then be added at frequent intervals to maintain proper electrolyte level.

An undercharge condition will not maintain a full charge and the electrolyte level will not change over a relatively long period.

2. The make-up water must be one of the following (in order of preference):
a. Distilled water.
b. Odorless drinking water (not mineral water)
c. Iron free fresh water.
d. Any available fresh water.

------ WARNING! ------

Never add acid or electrolyte solution.


Testing Electrolyte Solution

The general condition of a battery can be determined by measuring the specific gravity of the electrolyte solution. If the level is too low to allow taking a hydrometer reading, add make-up water to the correct level and then charge the battery 2 to 4 hours before taking a reading.

1. Insert the hydrometer tube into a cell. Fill the hydrometer barrel while holding it vertically. The float must not drag on the wall of the barrel.

2. Read the hydrometer:
1.250 or above: fully charge battery cell
1.250 - 1.225: full of half charged battery cell
1.225 - 1.150: half to low charged battery cell
Below 1.150: dead cell
1.000: water

Actual hydrometer readings may vary as a result of the electrolyte temperature, type of battery construction, or strength of electrolyte used.

3. Test each cell in the same manner.
4. If there is more than .050 (50 gravity points) variation between the highest and lowest reading, the battery should be replaced.

The hydrometer reading is of most importance during cold weather. A low specific gravity reading signifies the battery has less available power to crank the engine, booster batteries may be required; and the battery may freeze in low temperatures.

Charging the Battery

------ WARNING! ------

Do not smoke near the area where batteries are being charged. Fumes from batteries are flammable.


1. Connect the positive charger clamp to the positive battery terminal.
2. Connect the negative charger clamp to the negative battery terminal.
3. Connect the battery charger to a wall outlet of proper voltage.
4. Slowly charge the battery until the specific gravity of the solution is at least 1.240 at a temperature of 80°F (27°C).


If the electrolyte temperature nears 125°F (53°C), the charging rate must be reduced to prevent ruining the battery.

5. After the battery is properly charged, disconnect the charger from the wall outlet; disconnect the charger clamp from the negative battery terminal; disconnect the charger clamp from the positive battery terminal.

Cold Weather Battery Maintenance

The following instructions will help battery performance in cold weather.

1. After adding make-up water, charge the battery

The added water will dilute the electrolyte. This will lower the specific gravity of the electrolyte solution, lower the charge of the battery, and lower the freezing point of the electrolyte solution.

2. Keep the batteries fully charged either by operating the charging system or by using a battery charger.
3. Keep the electrolyte warm when the battery is not in use. The heat from an electric light bulb usually is sufficient.


Do not lay cloth or flammable material in contact with a lighted bulb. Do not lay a lighted bulb on the battery case.

4. Use starting aids as instructed for starting.
5. Use booster batteries as required. Connect the batteries as instructed below.

Connecting Booster Batteries
1. Using a pair of jumper cables, connect the red jumper cable to the "hot" terminal of the booster battery.
2. Connect the black jumper cable to the ground terminal of the booster battery.


Keep the red and black cable terminals from touching each other.




3. Connect the other end of the red jumper cable to the "hot" terminal of the engine battery.
4. Connect the other end of the black jumper cable to the ground terminal of the engine battery.
5. Start the engine using starting aids as instructed.

Disconnecting Booster Batteries

As soon as the engine starts:

1. Disconnect the black jumper cable from the engine battery ground terminal.
2. Disconnect the red jumper cable from the engine battery "hot" terminal.
3. Disconnect the black jumper cable from the booster batteries.
4. Disconnect the red jumper cable from the booster batteries.
5. Disconnect the booster batteries. Charge them to full capacity with a battery charger.

Checking Charge Rate
1. After starting the engine, the ammeter indicator should register to the right of zero, but should never be "pegged".

2. After the engine has been running, the indicator should be just to the right of zero.

If the indicator remains to the right of zero, or remains to the left of zero with an increase of engine speed, have the electrical charging system checked.

Cleaning the Battery
1. Mix a weak solution of baking soda and water. Apply the solution with a bristle brush.
2. Thoroughly rinse the battery and battery tray with clean water.

3. Apply grease to the battery cable clamps and terminals and to all threads.

Mechanical And Solid State Magnetos

The magneto supplies electrical energy to fire the spark plugs. The magneto develops low voltage current. This current passes through wires which are connected to the transformers installed at each engine cylinder. The transformers convert the low voltage to high voltage. The current then passes to each spark plug where ignition occurs. Earlier engines use a mechanical type magneto, later engines use a solid state magneto.

Solid State Magneto

The solid state magneto can be identified by a screw-on type of connector which contains all of the wiring to the separate transformers. The end of this magneto housing contains pulse activated solid state electronic components which do not require periodic maintenance or servicing. If an operational problem is traced to the solid state magneto, contact your AVSpare dealer.

The solid state magneto produces direct current (DC). Each "hot" wire is connected to the "POSITIVE" (+) terminal of each respective transformer. All negative terminals of the transformers are connected together in a common ground wire. Firing order is 1-5-3-6-2-4.

Mechanical Magneto

This magneto can be identified by the flat end cap having six wire terminals. Each wire is connected to a transformer according to the firing order of the engine. By removing the end cap, the rotor, brushes and contact points are accessible for servicing or replacement.

The mechanical magneto produces alternating current. Because AC current has reversing polarity, the "hot" wires for cylinders 1, 2 and 3 are connected to the "NEGATIVE" (-) terminals of the transformers, the "hot" wires for cylinder 4, 5 and 6 are connected to the "POSITIVE" (+) terminals of the transformers. The ground wires for the transformers are connected to the opposite terminals. Firing order of the engine and polarity involved for that cylinder is 1 (-), 5 (+), 3 (-), 6 (+), 2 (-), 4 (+).

Rotor and Flywheel Rotation

Normal engine flywheel rotation is counterclockwise when viewed from the rear of the engine. When barring the flywheel in direction of normal rotation, the magneto rotor disc rotates clockwise as viewed with the magneto end cap removed.

Removing the Magneto
1. Disconnect the magneto connector, or disconnect each wire from the magneto end cap.

2. Remove the magneto mounting bolts.

3. Remove the magneto.

Installing Contact Points and Condenser (Mechanical Magnetos Only)
1. Remove the magneto end cap.

2. Inspect the brushes attached to the inside of the end cap. If the brushes are worn excessively, replace the block assembly.

3. Remove the rear housing.

4. Remove the rotor disc.

5. Rotate the magneto coupling drive until the rubbing block is positioned on the top of a cam lobe.

6. Loosen the screws holding the point bracket. Install new points if they are burned or pitted.

Install a new condenser whenever points are installed.

7. Move the point bracket until the proper point opening is obtained. Correct gap is .017 inch (0.43 mm). Tighten the screws after adjustment is made.

8. Check the point gap. Loosen and adjust if necessary.

9. Install the rotor, housing and end cap.

10. Install the magneto to the drive housing, see the following instructions.

Installing the Magneto

The magneto must be statically timed with No. 1 piston on compression stroke.

1. Remove the flywheel housing timing cover.

2. Wipe the base of the valve cover; remove the cover.

Cylinders are numbered consecutively from front of engine to rear. No. 1 compression stroke begins when No. 6 exhaust valve begins to open.

3. See either the MAGNETO TIMING CHART below, or the plate mounted on the flywheel housing for compression ratio and timing dimension.
4. Turn the flywheel counterclockwise, as viewed from the flywheel, until No. 1 piston is coming up on compression stroke.

5. Continue turning the flywheel until the specified timing mark appears under the timing pointer.
6. Check both rocker arms for No. 1 piston. Both rocker arms must move freely.


If either rocker is tight, continue turning the flywheel until No. 1 piston is on compression and both rockers move freely.

Improper timing can cause raw gas to ignite in the exhaust manifold or stack when starting the engine.

7. Remove the timing plug from the magneto housing.

8. Turn the magneto coupling drive until the timing mark on the gear is centered in the timing hole of the housing.

9. The magneto coupling drive lugs should be aligned with the lugs on the magneto drive shaft.

If the lugs do not align, pull out, index and install the magneto drive shaft from the magneto drive housing. Do not turn the magneto coupling drive lugs; this would change the magneto timing.

10. Install the magneto to the magneto drive housing, but only tighten the mounting screws finger tight.

11. Install the magneto timing plug and valve covers.

12. Install, or connect, the transformer lead wires to the magneto end cap.

13. Check the magneto timing with a timing light.

Checking Magneto Timing

To check magneto timing, the magneto must be installed on the engine.

1. Remove the timing cover from the flywheel housing if it has not already been removed in preceding steps.
2. Connect a timing light in series with No. 1 cylinder spark plug wire.
3. Start the engine. Gradually increase engine speed to full load RPM.
4. Check the flywheel timing mark with the timing light. Compare the reading with the MAGNETO TIMING CHART value.

A mechanical magneto should maintain static setting when running.

A solid state magneto will automatically advance the spark 20° as engine speed is increased to full load speed.

5. If needed, advance or retard the engine timing by loosening the magneto mounting screws and slowly rotating the magneto housing.

6. When the correct timing mark is aligned with the timing pointer, tighten the magento mounting screws.
7. Stop the engine. Remove the timing light and install the flywheel timing cover.

Wiring Diagrams

Spark Plugs

Removing and Inspecting Spark Plugs
1. Disconnect wire and remove rubber cap from each transformer terminal. Do not pull on the ignition wire; the wire may break.

2. Remove rubber cap from each spark plug well; slide cap up wire.
3. Disconnect wire from spark plug terminal. Do not pull wire.

4. Remove the spark plug from each cylinder.

5. Examine the condition of each spark plug. Clean if necessary.

6. Check and set spark plug gap. Correct gap is .013 inch [0.3 mm]. Check both terminals on each spark plug.

7. Install spark plugs. Tighten to 18 lb.ft. (24 N·m).


Do not overtighten

8. Connect spark plug wire. Slide rubber cap down wire and cover spark plug well.
9. Connect ignition wire to transformer terminal. Install rubber cap over terminal.

Power Coupling System

Flywheel And/Or Front Power Take-Off Clutches

Checking Clutch Adjustment

While engaging the clutch to pick up the load, check the clutch adjustment. The clutch should engage with a hard push and distinct snap. If engagement is "soft", adjust the clutch.

Adjusting Clutch
1. Stop the engine and remove the clutch inspection cover.

2. Turn the clutch until the lock pin, engaged in the locking ring, is visible.
3. Pull the lock pin out and rotate the locking ring clockwise until the lock pin pops into the next notch.

4. Test the clutch adjustment. If still too "soft", rotate the ring to the next notch. If the adjustment is too tight-turn the ring back one notch.
5. Install the cover.

Lubricating Clutch

Lubricate the clutch bearings, 1 or 2 strokes each fitting.

1. Lubricate shift-collar and shaft; 1 fitting at top-left of center.

2. Lubricate the shaft bearing 1 fitting on top-rear of housing.
3. Lubricate the shift lever bearings; 1 fitting on each side of the clutch housing.
4. Lubricate pilot bearing; 1 fitting at the end of shaft.

Electric Set Generator

There are two types of Generators: SR4 and SRCR. To determine which generator you have, see the serial number stamped on the generator nameplate. The first group of numbers will be followed by either a "B", or a "T"; "B" designates a SR4 Generator, "T" designates a SRCR Generator. For a complete explanation of the serial number, see the ELECTRIC SET OPERATION INSTRUCTIONS.

The SR4 Generator is a brushless type generator. The SRCR Generator uses slip rings and brushes. Periodically inspect the brushes and/or slip rings for wear and appearance.

If the electric set generator is not of AVSpare design, see the manufacturer's instructions for the required lubrication and maintenance procedures.

Inspecting Slip Ring (SRCR Generators only)
1. Remove the two lower panels from the rear of the generator housing.
2. Inspect the slip ring color. The slip ring color may be shiny copper to straw, or chocolate to black, but the color must be uniform to indicate satisfactory operation.

If the ring is basically one of the above shades, but contains blotches of green, blue or black, clean the ring with an electrical cleaning solvent.


Do not use gasoline or carbon tetrachloride. Both solvents will dissolve insulation. The vapors from carbon tetrachloride can be harmful when inhaled.

Green blotches are caused by chlorine vapors, blue blotches are caused by sulphuric fumes, black blotches are caused by oil.

3. Inspect the slip ring for pitting. If the slip rings are rough, pitted, or worn eccentric, contact your AVSpare dealer. The rings must be reconditioned.
4. Check the following to determine the cause for pitting:
A. Check the generator nameplate rating. The generator load must be within this rating.
B. Check the brush tension.

Inspecting Brushes

The brush must move freely within the holder, but with enough spring tension to prevent brush flotation during operation.

If the spring is moved forward and the brush tension is greater than chart specifications, release the spring one notch. Excessive spring tension will cause excessive brush wear.

If brush tension is weak, push the spring forward into the next notch. If the spring is in the front notch, remove the brush and check the brush length. If the brush length is less than the minimum required, install a new brush.

Installing Brushes
1. Release spring tension.
2. Disconnect the lead wire from the brush and pull the brush from the brush holder.
3. Insert a new brush. Be sure it moves freely in the brush holder. Connect the lead wire.
4. Place a narrow piece of "00" sandpaper between the brush and slip ring with the abrasive surface against the brush. (Never use emery cloth as the emery contains small metallic particles which will damage the copper.)
5. Engage the spring in the middle notch.
6. Slowly pull the sandpaper from beneath the brush.
7. Remove all dust with a suction hose. If suction is not available, use a very low pressure blower. Do not use metal hose tips.
8. Check brush tension.
9. Install the two panels.

Lubricating Rear Bearing
1. Remove the two lower panels from the rear of the generator housing.
2. Remove the upper and lower grease fitting plugs.
3. Install the grease fitting in the upper threaded hole.

4. Lubricate with grease until clean lubricant appears at the lower threaded hole.

5. Wipe off the excess grease. Install the lower plug.
6. Remove the fitting from the upper threaded hole.
7. Start the engine and allow the grease to expand from the upper hole.
8. Stop the engine. Install the plug in the upper hole and wipe off excess grease.
9. Install the two panels.

Miscellaneous Maintenance

Tachometer Drive

The tachometer drive does not require periodic lubrication. If an angle adapter is used, the adapter must be lubricated periodically.

Lubricate the adapter; two strokes with a hand gun.

Shut Off

The shutoff must be checked so that if and when needed it will function properly. To prevent damage to the engine while making the required test, only authorized personnel should perform the checks. Contact your AVSpare dealer.