How critical is it that an engine maintains a reasonable temperature, Is there a problem with an engine running cool?

Andrew.

yup, it needs too be up too reasanable temp too run efficiently, you can overcool

it suffers when it has it cold..

like it suffers two when its to hot...

a engine doesn't rev freely when it has it cold....

Tks

Running too cold, the engine will experience extra wear, and oil tends to accumulate moisture if it dosen't get hot enough. Mixture will need to be richer, so economy will drop.

Also if you run continuously on rich mixtures you could suffer bore wash, oil contaminaton, spark plug fouling etc.

yes. car engines are designed to operate efficiently in a narrow temperatrue band, outside of that you're gonna get the type of problems mentioned.

If engine is too cool, the combustion process is going into heating up the block, pistons etc. rather than expanding gasses so you will loose power, and let's face it that is what it is all about