black smoke with breather on

[griffin90]

I have a Kohler 21hp Courage engine. I just placed fuel solenoid. When I start it engine smokes and sputters like it is being smothered' but if I take off the breather it runs fine- Breather is not new but it looks ok.Any suggestions?

 

[EngineMan]

I have a Kohler 21hp Courage engine. I just placed fuel solenoid. When I start it engine smokes and sputters like it is being smothered' but if I take off the breather it runs fine- Breather is not new but it looks ok.Any suggestions?

Its running too rich, if the smoke is black, try a new air filter, has the problem come from you fitting the new fuel solenoid.? if so check that out.