Great tip on helping you keep your Ford 300 Industrial engine up and running.

Recently we have noticed that some Zenith downdraft carburetors on Ford 300, which is also known as the Ford CSG649, industrial engines have had poorly adjusted automatic chokes. As a result the engine is hard to start, runs poorly, fouls plugs and emits smoke.

Here’s how to adjust these Zenith model 33 carburetors:

  1. If your shop’s ambient temperature is 70° simply open the choke plate 1/32″ so it is just off the choke bore.
  2. If not 70° loosen the three plate screws to open the choke plate 1/32″. Then adjust for temperature by rotating the choke cover one mark per each 5° of temperature difference from 70°. Rotate counter clockwise to lean the mixture if warmer than 70° and clockwise to enrich the mixture if colder than 70°.
  3. cover plate screws and check the choke shaft for free operation.