Fuels and Lubricants for Small Engines

Fuels and Lubricants for Small Engines UT Agricultural Extension Service

Jim Wills • Biosystems Engineering and Environmental Science Department • Extension • University of Tennessee UT Extension

Two Main Types of Small Engines on Lawn and Garden Equipment • Four-Stroke Cycle • Two-Stroke Cycle UT Extension

Cooling System • Most engines on lawn and garden equipment are air cooled • Fan on flywheel circulates air over engine for cooling while engine is running • Water cooled engines have radiator and liquid coolant circulating in water jacket around engine UT Extension

Flywheel/Fan UT Extension

Four-Stroke Engines • Four strokes* of the engine for one power cycle • Stroke 1 – Intake • Stroke 2 – Compression • Stroke 3 – Power • Stroke 4 – Exhaust * A stroke is one up or down movement of the piston in the cylinder UT Extension

Four-Stroke Operation UT Extension

Typical Four Stroke Lawn and Garden Equipment • Push-Type Lawn Mowers • Lawn Tractors • Garden Tractors • Pressure Washers • Chippers/Shreaders • Garden Tillers UT Extension

Two Stroke Operation UT Extension

Typical Two-Stroke Equipment • Chainsaws • Weed Trimmers • Leaf Blowers • Hedge Clippers • Air Compressors • Small Garden Tillers • Some push type lawnmowers UT Extension

Four-Stroke Engine Characteristics • Separate fuel tank and oil reservoir • Heavier/larger than same HP two-cycle • Cannot be tilted much to side • Longer engine life • Larger HP uses UT Extension

Two-Stroke Engine Characteristics • Fuel and oil are mixed in fuel tank • No separate reservoir for oil* • Can be operated on side and upside down • Lighter/smaller for given HP • Shorter overall engine life • Usually more noise and smoke * Some boat motors and motorcycles havea reservoir UT Extension

Main Causes of PrematureSmall Engine Failure(Short Engine Life) UT Extension

Dirt! • 60% to 70% of all failures are caused by dirt* getting into engine *Dust, insects, bits of grass, etc. UT Extension

Service air filter on a regular basis (usually once a season) • Service more often under dusty or adverse conditions UT Extension

For every gallon of gasoline used, the air filter must clean 10,000 to 11,000 gallons of air UT Extension

Air Filter – Paper Type UT Extension

Carburetor UT Extension

Failure to use proper oil* * Viscosity (thick or thin) * API Classification (SJ, SL, Etc.) UT Extension

Failure to change oil on a regular schedule • Mileage • Hours of use • Time of use (weeks, months, etc.) UT Extension

Failure to maintain proper oil level in crankcase • Check dip stick • Check oil level plug UT Extension

Checking Oil Level UT Extension

Failure to use clean, fresh fuel • Dirty fuel tank • Dirty fuel can • Dirty funnel • Trash/dirt around fuel cap UT Extension

Install a fuel filter on fuel line if not factory equipped UT Extension

Fuel Filter UT Extension

Use a suitable fuel container to prevent fuel contamination and insure safety • Metal cans will eventually rust inside • Plastic containers will not rust • Use a funnel with mesh filter UT Extension

Can Good Plastic Fuel UT Extension

Failure to use proper fuel • Unleaded fuel is cleaner burning • Choose proper fuel octane level • Do not use fuel containing alcohol • Use lead substitutes if 1974 or older UT Extension

Operating tips to extend engine life • Let engine idle for two minutes before stopping • Never stop under load • Avoid stalls and sudden impacts UT Extension

Avoid Impacts UT Extension

Flywheel Keyway UT Extension

SAFETY!!! • Use approved fuel containers • Never fuel a hot engine • Stop engine before making repairs or adjustments UT Extension

Motor Oils UT Extension

Castrol Brand Oil UT Extension

Functions of Motor Oil • Lubricate moving parts • Seal around gaskets, seals, piston rings • Clean contaminates from engine parts • Remove excess heat from engine UT Extension

Oil container has information on oil quality and viscosity UT Extension

API (American Petroleum Institute) circle contains API Service Classification and Viscosity UT Extension

API Circle UT Extension

VISCOSITY • Is the oil thick or thin? • Affected by temperature • Affected by shear of oil molecules in lubrication process • All oils are tested at same temperatures to establish viscosity rating UT Extension

Viscosity Values • SAE 0W, 5W, 10W, 15W, 20W • SAE 30, 40, 50 • SAE 10W-30, 5W-30, 15W-50, 10W-40, etc. • “W” means suitable for wintertime use (cold temperatures) • “SAE”- Society of Automotive Engineers UT Extension

API Service Classifications • “S” - for gasoline engines (S- Spark ignition) • “C” - for diesel engines (C- Compression ignition) UT Extension

Gasoline Classes • SA, SB, SC, SD, SE, SF, SG, SH, SJ, SL • SA is lowest quality • SL is highest quality UT Extension

Diesel Classes • CA, CB, CC, CD, CE, CF, CG, CH • CA is lowest quality • CH is highest quality UT Extension

Petroleum Based Oils • Base stock of about 85% oil by volume • Additives of about 15% by volume • Additives include detergent, anti-oxidation, anti-corrosion, extreme heat, extreme pressure, anti-rust, etc. UT Extension

Value of Oil Additives? • Slick 50, T-Plus, STP, Motor Honey, etc. • Usually not worth the price !!! UT Extension

T-Plus Additive UT Extension

Why Change Motor Oil? • Replace additives • Remove contaminants ( water, acid, carbon, etc. UT Extension

When to Change Motor Oil? • At recommended mileage (3,000 on cars, trucks, campers, etc.) • At 50 hours on small engines • More often under severe conditions (pulling heavy loads, steep climbing, etc.) • Change when oil is hot, not cold UT Extension

Changing Brands of Oil • You do not have to use the same brand of oil forever in a given engine • To change brands, drain old brand and replace with new brand – change oil filter at same time • Use same viscosity UT Extension

Oil for Your Small Engines • SAE 30* • SAE 10W-30 • Synthetic oil * Above 40 degrees F UT Extension

Fuels and Lubricants for Small Engines