Hi Guys,

Recently, I was using my Generac 5550 generator with a 10HP Briggs & Stratton OHV, model 204412, Type 0142 engine, and it started running rough and puffing black smoke. So I bought the repair manual. Took everything apart to the piston, cleaned the carbon off the pistons and valves. Cleaned everything up on the cylinder head, replaced all gaskets with new ones. Put it back together, and adjusted the valves properly. I changed the air filter and spark plug, changed the carburetor with a new one. Fired it up and it still lacks power, runs rough and spits out some black smoke. I pulled it apart several times readjusting valves, cleaning carbon off the plugs. Put it back together but it still runs rough. The only thing I noticed, and I am not sure about is, there was some oil sitting at the bottom of the valve rods, and noticed that the valve cover which has a breather tube, seemed a bit oily? When I pull the breather tubing off, and smell it, it smells like fuel, and had some oil residue there. Not sure if this could be the problem? Or what it exactly would be? Any ideas are certainly appreciated. Oh and a leak down test, showed minimal leakage, nothing of concern?? Thanks. Mike