John Deere Powertech 6068 Engine

Tools: JDE 820 or JDE 83 Flywheel Turning Tool, JDE 81-4 Timing Pin

1. Remove rocker arm cover with ventilator tube.
2. Remove plastic plugs in engine timing holes on front side of flywheel.
3. Rotate flywheel clockwise with Flywheel Turning Tool until Timing Pin engages timing hole; No. 1 cylinder rocker arms loose at TDC.
4. If not at TDC, remove timing pin, rotate flywheel one complete turn, and reinstall pin.
5. Check valve clearances with engine cold.
6. For 4-cylinder: adjust No. 1 and No. 3 exhaust and No. 1 and No. 2 intake at No. 1 TDC; rotate 360° and adjust remaining.
7. For 6-cylinder: adjust No. 1, No. 3, No. 5 exhaust and No. 1, No. 2, No. 4 intake at No. 1 TDC; rotate 360° and adjust remaining.

⚠ Do not run engine with air cleaner removed.

1. Inspect air cleaner every 100 hours; replace filter every 600 hours or yearly, whichever comes first.
2. Loosen hose clamp and attaching strip; clean rubber tube at cleaner.
3. Ensure rubber tube is in good condition and new filter is clean and installed properly.
4. Start engine and check for leaks.

⚠ Escaping diesel fuel under pressure can penetrate skin.

Tools: Backup wrench

1. Loosen bleed plug on fuel filter.
2. Operate primer pump lever on fuel transfer pump until air bubbles are expelled and clear fuel escapes.
3. Tighten bleed plug.
4. If engine will not start, loosen fuel supply pipe at pump and prime until free of air; retighten to 22 ft. lb. (30 N•m).
5. If still not starting, loosen fuel line at injection nozzle and crank with throttle full until fuel without air flows; tighten to 20 foot lb. (27 N•m).

Tools: Oil drain hose, Hand pump (optional drain pump)

1. For marine generator sets, remove plug from base frame outlet and screw in owner-supplied drain hose.
2. Open valve at oil pan outlet and drain oil into suitable container.
3. Close valve, remove drain hose, and replace plug.
4. Refill engine with recommended oil.
5. For propulsion engines with optional drain pump, remove dipstick, unscrew dipstick tube, insert hand pump to bottom of oil pan, and drain by pumping.
6. Replace dipstick tube and dipstick; refill engine with recommended oil.

⚠ Overtightening can damage filter housing.

Tools: Filter wrench

1. Use filter wrench to remove old filter; dispose in approved manner.
2. Make sure gasket from old filter is removed and discarded.
3. Lubricate rubber gasket on new filter and screw on nipple until gasket meets sealing surface.
4. Using hands only, tighten filter one-half turn farther.
5. Fill engine with recommended oil; start engine and check for leakage; stop and check oil level.

1. Drain the cooling system.
2. Remove cooling water pipes between heat exchanger and water pump inlet.
3. Disconnect hose to seawater pump.
4. Unscrew attaching bolts holding heat exchanger to expansion tank.
5. Remove bolts holding heat exchanger cover.
6. Wash core inside and out; clean accessible parts of housing.
7. Reassemble using new gaskets and sealing rings.

⚠ Cooling water is extremely hot; allow engine to cool before working.

1. Stop engine and allow to cool.
2. Close seacock.
3. Remove pressure cap from expansion tank; open cooling system air vent on turbocharger if applicable.
4. Open drains on exhaust manifold and engine block; drain fresh water system.
5. Pour clean water into expansion tank until drain water is clear; close drains.
6. Fill with recommended coolant mixture; close air vent.
7. Open seacock; start engine and check hoses and connections for leaks.

⚠ Keep extra impeller and cover gasket onboard.

Tools: Water pump pliers

1. Remove pump end cover.
2. Remove impeller with water pump pliers; remove all pieces of failed impeller.
3. Clean inside of housing.
4. Press in new impeller and place sealing washer in outer end of impeller center.
5. Replace cover using new gasket.

⚠ Dirt can be washed into fuel injection system causing severe damage.

1. Turn off the fuel.
2. Open filter drain plug and drain the filter.
3. Turn filter clamp counterclockwise until cartridge slides out.
4. Install new filter cartridge 24-51005 after ensuring mounting plate surfaces are clean.
5. Turn on the fuel.
6. Bleed fuel system if opened.

Tools: Scraper or steel brush

1. Drain raw water from heat exchanger.
2. Remove zinc holders from back of tank and from front and port side of heat exchanger.
3. Scrape or steel brush zinc electrode clean.
4. Replace zinc if more than 50% eroded.
5. Reinstall zinc holders with clean threads and good metal-to-metal contact.

1. Shut off sea cocks before opening drain cocks.
2. Drain seawater cooling systems completely.
3. Drain seawater supply lines and wet exhaust line.
4. Loosen seawater pump cover and drain pump.
5. Check freshwater antifreeze mixture; refill water if necessary.

⚠ Use protective clothing and open filler cap carefully when engine is warm.

1. Check expansion tank water level; should be about 1 3/4 in. (4-5 cm) below filler cap sealing surface when cold.
2. Check crankcase oil level; keep between the "waffled area" and the "oo".
3. Check fuel tank level and open any fuel valves.
4. Check reverse gear oil level per Gear Owner's Manual.
5. Close seacock, clean strainer, and reopen seacock.
6. Place battery switch in ON position.