Hercules — Also, disconnect the water temperature gauge thermocouple.

A Hercules service procedure — check it applies to your exact model before use.

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Procedure

1. 3. Disconnect and remove the air cleaner hose from the manifold.
2. 4. Disconnect the exhaust pipe from the manifold.
3. 5. Disconnect the fuel lines and remove from pump and nozzle holders.
4. 6. Remove the front and rear cylinder head covers, rocker arm assemblies
5. and push rods. ,
6. 7. Remove the cylinder head nuts and lift the cylinder head assembly
7. carefully from the engine (manifolds may be removed with the heads).
8. 8. Remove the oil pan and lubricating oil pump and lines.
9. 9. Remove the piston oil spray nozzle assembly from each cylinder.
10. 10. Carefully scrape the carbon deposit from the top of each cylinder
11. bore so that the pistons can be removed without damage to the rings.
12. ll. Turn the engine so that No. 1 and No. 6 connecting rod caps can be
13. removed and the piston and rod assembly pushed carefully upward
14. -with a block of wood or hammer handle, Illustration No. 10, to remove
15. from the engine.

Source: manual:HERCULES D4800 Maintenance Manual .pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.