Kubota — Installing the Injection Pump Shims
Repair & overhaul · Fuel injection pump
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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Before you start
- Do not attempt to disassemble and repair the injection pump; replace the entire pump if defective.
Procedure
- Insert the control rack pin firmly into the groove of the fork lever and thrust lever.
- Serial numbers up to 489290: insert the same number of shims as used before.
- Adding/subtracting a 0.0059 in. (0.15 mm) shim advances/delays timing approx. 1.5 deg.
- Apply liquid-type gasket (HIGH TACK or equivalent) to both sides of the shim.
- Serial numbers 489291 and up: apply sealant to both sides of the soft metal gasket shim.
- Use the same number of new gasket shims of the same thickness when replacing.
Tools required
- Sealant (HIGH TACK or equivalent) Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Shim 0.15 mm changes timing approx. 1.5 deg (up to s/n 489290)
- Shim 0.05 mm changes timing approx. 0.5 deg (s/n 489291 and up)
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.