Cummins/Onan — Vacuum Pulloff Diaphragm Adjustment
Adjustments · Choke vacuum pulloff diaphragm assembly
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Procedure
- Apply a vacuum of at least 152.4 mm (6 inches) of mercury to fully pull in the choke piston rod.
- Insert a 8.5 mm (0.335 inch) drill rod between the choke plate and the carburetor throat.
- If necessary, bend the choke piston rod at the point shown in Figure 6-4 until the lip of the choke plate just touches the drill rod. Use two pliers to bend the link.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 152.4 mm (6 inches) of mercury
- 8.5 mm (0.335 inch) drill rod
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.