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Old 01-25-2010, 09:57 PM   #27 (permalink)
rmay635703
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Join Date: Jun 2008
Location: Somewhere in WI
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Quote:
Originally Posted by gjgerhard View Post
I just learned something the hard way and I'm making an effort to tell people about it.

However, I discovered that switching off the engine while in traffic can damage it, which is what happened to me. Twice.

Here's why: there are two ways to stop an engine that's not a diesel: you can switch off the ignition; you can shut off the fuel. If I ever go back to doing this, it will use the second method. What I was doing, and what caused the damage, is I would be driving along at elevated rpms, I would depress the clutch and switch off the ignition, and wait for the engine to stop turning.

While the engine is spinning down to stop, it continues to ingest a fuel/air mixture in the cylinder that is not getting burnt. Gasoline is horrible as a lubricant, and is actually quite effective for washing lubricants away. So what I was doing was washing away the thin layer of oil in my engine's cylinders, and eventually the rings started to complain.
Greg in Seattle
Sorry to hear about your motors, good reason to let them rev down a tad before key off.

Good thing my subaru 360 has a electric fuel cutoff when I shut off the key (a necessity on a gravity fed system) Also my 2 cycle continues to ingest oil as it has torque induction OOH.
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