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Why should fuel injectors be tested regularly? Isn't enough just to overhaul them at stated intervals?

27 Sep '19, 10:43

Sept. 27, 2019, 10:43 a.m.
KnowledgeBase's gravatar image


Makers define overhaul intervals for fuel injectors based on their statistics and research. However, fuel quality is a major influencer on injectors lifetime and maker can not foresee what kind of fuel the owner will buy for the vessel. That is why vitally important to monitor core engine parameter and inspect fuel system component (injectors are the first to check!) if any combustion abnormalities observed.

Dirt from bad fuel can come in between the valve and the seat and cause the injector to leak. A leak can be caused by a bent or stuck valve spindle which causes incorrect or no seating at all. Old nozzles have excessive wear between valve stem and nozzle body, which leads to leak as well.

Leaking injectors can cause:

  1. Reduction in engine efficiency
  2. High exhaust temperatures (it is a good indicator of leaking injector)
  3. Turbocharger surging
  4. Scavenge fires
  5. Carbon formation due to unburnt fuel
  6. Lifting of the cylinder relief valve
  7. Excessive smoke at partial loads
  8. Contamination of lubricating oil

Cleaning and operational test of fuel injectors at 1500 - 2000 RH should never be neglected. Same to be done if a single-cylinder high exhaust temperature observed.

Fuel injector leak pipe

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27 Sep '19, 11:04

Sept. 27, 2019, 11:04 a.m.
cheng's gravatar image

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