If a diesel engine turned over freely but...

Question 1 / 270705eccefa3bacbc34ba4d47deb

Question 1 of 270705eccefa3bacbc34ba4d47deb

If a diesel engine turned over freely but failed to start, the cause could be __________.

Question 1 of 27070

If a diesel engine turned over freely but failed to start, the cause could be __________.

🔍 Key Concepts

• basic diesel engine starting requirements: air, fuel (clean and in proper condition), and compression • effect of fuel contamination (like water in fuel) on combustion • how temperature and viscosity of lube oil affect cranking speed

💭 Think About

• Ask yourself: If the engine is cranking at normal speed, which problems are less likely to be the cause? • For each choice, decide: would this make it hard for the engine to turn over, or hard for it to actually fire and run once it’s turning? • Think about what happens inside the cylinder if the fuel cannot ignite properly even though the engine is spinning normally.

✅ Before You Answer

• Verify which options would mainly affect cranking speed or resistance to turning rather than combustion. • Check which condition would most directly prevent proper fuel atomization and ignition in a diesel engine. • Eliminate any choices that would more likely cause slow or difficult cranking instead of a free‑turning engine that just won’t start.

Question 1 of 27070

If a diesel engine turned over freely but failed to start, the cause could be __________.

water in the fuel

cold lube oil

excessive starting air pressure

excessive fuel pressure