Hi,

I have a B & S 16Hp Vanguard motor that runs hydraulic tools. The motor was smoking and running rough so I replaced the oil, gas, and air filter. I started it up with out the oil filter on and the motor runs perfect. I reinstall the air filter and the motor begins to choke out and run rough. I take the air filter off and it runs fine again. What could be the cause of this? Anybody?? :confused:

Carburetor sounds like it is running rich(more fuel than needed), without filter you have more air, sounds like if you lean the carburetor(less fuel), it will be a good mix with less air?

Hi,

I have a B & S 16Hp Vanguard motor that runs hydraulic tools. The motor was smoking and running rough so I replaced the oil, gas, and air filter. I started it up with out the oil filter on and the motor runs perfect. I reinstall the air filter and the motor begins to choke out and run rough. I take the air filter off and it runs fine again. What could be the cause of this? Anybody????:confused:
Thanks for your reply. The problem ended up being a oil soaked air filter. Upon first look at the filter it looked clean. Put a new one on and problem solved.

With the restriction of air, gave you more fuel, a rich condition, the new filter allowed more air(leaned the fuel)

Your carb needs either cleaned or adjusted, both probably would not hurt being performed.