How long do you run the engine each time?

[CAPTAIN FANTASTIC]

No engine likes idling; whether petrol or diesel, especially, if the engine is old; idling does not allow the oil to circulate fast and more often than not, certain engine parts will suffer from oil starvation.

Is not the rule of thumb start diesel engine and go, idle before switching off and the opposite for a petrol engine?

 

[vyv_cox]

I suggest there are two particular issues.

Running the engine from cold at tickover, particularly not under load, causes condensation of various combustion products on the bores, which is the primary cause of glazing. Run at cruising revs as soon as it has started to get the engine to working temperature as rapidly as possible.

At tickover, or low revs, once the engine is up to temperature is a different problem. Combustion in these conditions is incomplete and carbon can accumulate on the exhaust valve and passages as a result. Engine performance will suffer, hence the 'italian tune-up', run for ten minutes or so at maximum revs to clean the carbon out. This method, but not the name, is in the Yanmar workshop manual.

 

[ChiPete]

I'm glad I am not berthed next to you!

10 minutes at high revs sounds like an inordinate amount of time and similarly my understanding was that cooling down only really applied to those with turbo chargers?

Don't worry, she's very quiet and doesn't smoke...no, not SWMBON

Seriously though, 1200 rpm? High revs? Surely not?

There's no turbo, I was simply told (by a fella from Yanmar) that it's best practice to warm the engine above tickover and not to simply switch it off immediately after a long motoring run as the entire system hasn't had the chance to cool down.