Priceless Aviation Products 747B, Technical Manual And Parts List, Page: 20 / 42

Technical Manual & Parts Lists
15
Engine Oil & Filter
Check engine oil daily and after every 4 hours of operation. Unit must be setting level when
checking oil. Refer to engine manual and maintenance schedule for oil recommendation and capacities.
Use 5W30 Motor oil.
Change the engine oil and filter after the first 5 hours of operation, per the engine manufacturer’s
recommendations after that. If tug is being operated in extremely dirty conditions, then it is
recommended oil being changed more frequently.
General Engine Maintenance
Detailed instructions and recommendations for break-in and regular maintenance are specified in
the respective Engine Owner’s manual. Please refer to this manual for engine servicing, lubricating oil
levels with quality and viscosity recommendations, bolt torques, etc. The engine warranty is backed by
engine manufacturer. Special attention should be paid to applicable data which will not be duplicated
here.
V-Belt Maintenance
Most belts stretch after the first few hours of operation. It's best to check the tension frequently at
first. Inspect the tension after eight hours of operation, and then check it again at 150 hours, thereafter
twice a month. The rule of thumb for tension is between one-quarter and one half of an inch of
deflection when firmly depressed with your thumb at mid span. Too much tension will impose excessive
load; too little causes slippage and excessive belt wear.
Belts that squeal during acceleration or when operating at full load usually have slippage, never
add a lubricant to the belts. Squealing merely indicates that the belts need to be tightened.
Preventive maintenance tips include regular inspection for nicks, cuts, abrasion, and glazing. If
you find problems replace the belts. The belts must be replaced in matched sets. Never replace only one
belt.