Cummins/Onan 6.3 NHEL / 6.5 NH — Choke Pull-off Diaphragm Adjustment
Adjustments
For the Cummins/Onan 6.3 NHEL / 6.5 NH, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NHEL
Procedure
- Remove the complete air filter assembly to provide access to the choke plate.
- Disconnect diaphragm hose from intake manifold and apply 4 to 18 inches (102 to 457 mm) Hg vacuum to the diaphragm.
- Apply light finger pressure against the choke lever to take up all freeplay in the pull-off linkage.
- Check alignment of diaphragm stem, pull-off linkage, and slot in choke lever; correct as required.
- Measure distance between choke plate and bottom of carburetor; bend diaphragm mounting bracket to obtain 0.39 to 0.43 inches (9.9 to 10.9 mm) clearance.
- Move choke lever back and forth to check for free movement; verify choke does not bind or stick.
- Remove vacuum supply from diaphragm and install filter assembly on carburetor.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 0.39 to 0.43 inches (9.9 to 10.9 mm) clearance
Full service-parts list: Cummins/Onan NHEL →
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.