Smelly outdoors heating furnace (smells, chimney, gas, electric)

[Sudcaro]

We have an old heating furnace, located outdoors.
I always thought it was electric but it seems to be a gas one, although I'm still unsure about it - we've rented this house for under a year, I must say I never quite paid attention to that detail...
Anyway, I've just walked near it and it smells really bad there, not sure whether this odor is gas or something else. There is some sort of chimney on it, the smell obviously come from out there.
I had never noticed that before today, and had not noticed that last winter. I guess hubby never smelt anything either...
I would like to know if any of you have/had a similar system and if that smell is "normal", or if I should get worried (more than I already am) and get someone check it asap...
Your opinion?

[motormaker]

Might want to call the gas company to take a look at it.