I've got a Genesis Silver B, born 2003.

Up till now it has worked flawlessly.

However, over the last few months I'm seeing a black sooty coating on my food. It only seems to happen on food cooking in the rear right side of the grill. I've brushed the grate and flavorizor bars, but the soot is still there.

On red meat I can't really tell, but on chicken breast or corn on the cob it's really obvious.

Any ideas?

so how do the flames look ? or do you have so much grease in it that its smoldering or catching fire ?

Clean the inside of your hood. It may be falling from there.

It builds up and eventually starts flaking off like paint.

Do you coat you food with oil? Sometimes if the grill is hot, the oil can drip onto the burner and smoke and/or burn, which may leave a black soot-like mark on food such as chicken breast. I have seen this when I use a little too much olive oil (which has a relatively low smoke point) on a hot grill.

I'd first check the flames on the burner and make sure they are nice and blue. if they are quite yellow or orange then you aren't getting enough air mixture and the propane is burning rich and will create soot. check the air intake screens where the burner tubes meet the gas manifold by the valves to make sure nothing is partially blocked off.