OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Kirby H4-4A engine rebuild

I've attached photos of the complete mower after hosing off all of the cobwebs and dust and a closeup of the engine. Motor mower manufacturers seem to have this mania for painting everything on the engine - carby, springs, levers, engine itself and cowling.

After cleaning I removed the throttle cable, unbolted the engine and slipped it off the mower base. The cowling comes off easily though the fuel feed passes through it. When doing this, take note of the throttle assembly - how and where the throttle cable attaches, where the return and governor springs are attached and the positions of the two rev limiting screws.

The carby assembly comes off easily and once removed, I sprayed it liberally with carby cleaner and put it aside. Once again I took care not to disturb the mixture and idle screws.

The head is held on with 8 bolts - 3 long and 5 short. Two of the long screws have loose collars.

The remaining photos are of the partially stripped engine.



The beast after hosing off.



The Kirby engine - I'm surprised that they don't paint the spark plug as well ....



Rear of the engine (output shaft side). The oil seal has to be drilled for removal. The output shaft is a standard keyed 5/8" diameter stepping up to 3/4" at the seal.



Front of engine with cowling and starter gear removed. The keyed flywheel can be removed safely with an appropriate puller. Timing assembly and points are underneath.



Inlet/exhaust side with valve cover/breather removed. The lever is linked to the internal governor.



Interestingly, there was nothing on the engine to identify the model - only a riveted aluminium plaque fixed by Kirby

More soon,
Chris