Hi, I just joined after finding a simple answer to a question I was unable to get answers for from anywhere, this site is priceless. I now need to find a way of sorting out what appears to be over rich running. The model is a 281707 12HP 1990 Briggs on a ride on. It is unmodified. When running it tends to puff dark sooty exhaust gas and also hunts a lot under load until it settles down. I removed the existing spark plug and cleaned and adjusted the gap. It is difficult to start but once running tends to cut out or alternatively over revs on idle when hot. Also hard to restart when hot. When I re-examined the plug it was very sooty after just a few minutes running. As far as I can see the choke is not set to cold start although the linkage (part 216) is not fixed. I am about to fix it having found the answer on here but I am certain that this is not the problem as the choke is not in use. I think it is running too rich but any suggestions on what is going on and how to fix would be great. Thanks in advance.
