1981 Plymouth Arrow Pickup Base, Automatic TransFACTORY OEM SERVICE PROCEDURE

Orifice Spark Advance Control: Operation

Vacuum is obtained by a vacuum tap just above throttle valves of carburetor. This type of tap provides no vacuum at idle, but provides manifold vacuum as soon as throttle valves are opened slightly. Proper operation requires air tight fittings.

Fig 1: Close-Up View of OSAC Valve
G09337130Courtesy of CHRYSLER GROUP, LLC
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.