Troy-Bilt 78 Manual De Usuario

The valves and valve seats can be serviced by grinding and lapping or the head can be replaced. Depending on 

local machine and labor costs, it is probably more economical to replace the cylinder head versus servicing the 
valves.

To service the valves:

NOTE: Servicing valves during the warranty period will 

void the warranty. Warranty valve repairs are to be 
accomplished by replacing the cylinder head. 

1.     Remove the cylinder head by following the steps 

described earlier in this chapter.

2.

Remove the rocker arms by:

2a.

Remove the jam nuts.

2b.

Remove the fulcrum nut.

2c.

Slide the rocker arms off of the rocker studs.

3.

Remove the valve retainers by applying light finger 
pressure and moving the retainer so that the valve 
stem passes through the large part of the “keyhole” 
opening in the retainer. See Figure 9.10.

NOTE: The valve keepers are not interchangeable.

NOTE: The exhaust valve has a cap called an “adjuster” 

on it. The cap needs to be pulled off before the 
keeper can be removed. See Figure 9.11.

NOTE: If the engine has a dropped valve, remove the cyl-

inder head, inspect the valve and the piston for 
damage.

Press down 
and slide off

Secondary valve

keeper

Valve keeper

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