Cummins/Onan 4.0 MCCK / 6.5 MCCK — Carburetor Float Adjustment
Adjustments
For the Cummins/Onan 4.0 MCCK / 6.5 MCCK, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan MCCK engine
Before you start
- Be careful not to lose the buoyancy spring or tension spring on the viton tip float needle and seat assembly.
Procedure
- Disconnect governor, choke leads, flame arrester and fuel line from carburetor.
- Remove the two bolts holding the carburetor on the intake manifold assembly.
- Remove the four Phillips head screws on top of the carburetor and lift it off.
- Invert carburetor and check float setting; float should be 0.02 +/- 0.02 inch above machined mating surface (without gasket); bend float tab as required.
- If resetting level, loosen screw near float valve axle and bend float arm to position float flush with top edge of float bowl.
- Reassemble carburetor; reinstall on intake manifold, connect fuel line and install flame arrester.
- Check carburetor for proper operation.
Tools required
- Phillips screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Float 0.02 +/- 0.02 inch (0.51 +/- 0.51 mm) above mating surface
Source: Cummins/Onan operator's 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.