It's funny you should mention it because mine went through a strange smelly phase too - at first I couldn't work out where the smell was coming from but the wierd thing is that it smelt like fuel - by that I mean a gas/oil/petrol type smell, and it wasn't the paraffin heater in the same room either as I kept sniffing that to check!
Eventually (I think) I worked out it was burning linseeds that had got stuck inside, so turned it upside down and gave it a good shake out and now I do that from time to time and all is well.
I'm not sure what you can do about a yeasty smell though.
