Kubota — Fuel Tightness of Delivery Valve
Testing & diagnosis
From a Kubota service manual covering: Hurth HBW 100, Hurth HBW 125, Hurth HBW 150, Hurth HBW 250, Hurth HBW 35, Hurth HBW 50, M-25XPB, M-35B, M-40B. Check it applies to your exact model before use.
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Procedure
- Remove fuel injection lines and glow plugs.
- Set pressure tester onto fuel injection pump.
- Turn flywheel and raise pressure to approx. 2133 psi (150 kgf/cm2) (14.7 MPa).
- Turn flywheel back about half turn; measure time for pressure drop from 2133 to 1990 psi (150 to 140 kgf/cm2) (14.7 to 13.7 MPa).
- If measurement is less than limit, replace delivery valve.
Tools required
- pressure tester Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Pressure drop from 2133 to 1990 psi (150 to 140 kgf/cm2) (14.7 to 13.7 MPa)
Source: Kubota 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.