Maintenance Is Optional

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Maintenance Is Optional

• THE FAILURE OF LAWNMOWER ENGINES

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Several Engines Compared

• 5 engines compared - failure - 2 failed
  engines - 2 working engines

• Negative Features
• - Grass/ oil mixture on restricting airflow
• - Lack of oil
• - Grass/ oil contaminated air filter
• - Broken breather tube
• - Bad maintenance

Positive Features - Over-Speed Protection -
Positive Oil Pump - Metal cam shafts and
gears - All had engine brakes - Structural
Webbing - AlSi con rods (hypoeutectic) - AlSi
crank case (hypoeutectic) - Easy Start
(Compression/ Release Feature)
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Non-lubricated cap
Lubricated cap
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Fracture surface (SEM)
Galled surface
Hypoeutectic AlSi
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Conclusion

• Basically good engine but old
• Poor materials choice for breather tube
• Causes
• Lack of maintenance
• No oil
• - Breather tube system
• Solutions
• Engine doesnt work when low oil
• LED light turns on