when the exhaust gas emitted from a petrol engine that is running very rich what colour is it likely to be?

Answer 1

I think the ideal colour of the exhaust gas emitted must be colourless. Any other colour indicates problem, The white colour indicates leakage of lube oil in the engine which when burns gives white colour, Black indicates that the fuel is not burning properly and engine needs tuning.

Answer 2

I love the variety of answers!
For the record, my vote is:
Black (sooty) = too much fuel
White (steamy) = leaking water
Blue (Grey-blue / bluish-white) = oil

When the engine is only a little rich, the exhaust would still be colourless. If it has a catalytic converter, it is intended to run a little rich. Running rich reduces the formation of nitrous oxides in the engine and the catalytic converter oxidizes the remaining fuel in the exhaust. If the catalytic converter were removed or was no longer functioning, the exhaust would be rich in unburned fuel but still be colorless. Only if there is enough fuel to make soot would you be able to see it in the exhaust.

Answer 3

It will have a lot of soot...or carbon. Which is black. Blue means you are burning oil. The carbon will actually build up quite heavily on the tail pipe, and possibly above or around it as well. But black is what you should look for, if your engine is running rich.

Answer 4

I think that blue smoke indicates too much gas

Answer 5

The smoke will be black, white smoke means you are burning coolant, blue smoke means oil

Answer 6

black for being to rich blue when burning to much oil

Answer 7

if its gas problems then its black or if its blue could be vacum or oil burning.

Answer 8

i think that the gas will be white

Answer 9

Black, get it checked out straight away

Answer 10

Definitely black Regards Mick.