Carburetor - ROCHESTER E2ME 2-Bbl: Testing: Testing

Hard starting or poor warm-up performance may be due to a leaking vacuum break (choke pull-off) unit. If the vacuum break is leaking and not allowing the choke valve to open to the proper position, a cold engine may load up with fuel and produce black exhaust smoke.

The following testing procedure may be used to test vacuum break units:

1. Determine whether the vacuum break has a bleed orifice. If so, plug bleed orifice. Most rear (secondary side) units have a bleed orifice, while most front (primary side) units do not.
2. Using a hand-held vacuum pump, apply 15 in. Hg to the vacuum break unit. Ensure that the plunger moves into its full travel position, and holds that position for at least 10 seconds. If not, replace vacuum unit.