I might have missed it, but did you check the valve clearances?
Id try that, on most the inlet is closed up a bit.
It will probably have a graphite head gasket, if it cant be reused you could get a metal gasket off an older briggs and use it.
Remove the nut that holds the starter cup on and check the flywheel keyway is not sheared or defomed. Thats a common fault with mowers with bar blades. Incorrect timing can give you mixture like symptoms.
Loose inlet manifold, or if its cracked or another common thing is the shroud or cover or air deflector wearing through the plastic inlet manifolds. If its been loose at the two little 1/4" headed bolts the gasket may also be damaged.
(sorry, didnt read all of each post above)
You could put the motor on any other Victa, but in the case of the utility it will need to be a power torque base and it would want to be drilled so that the motor faces forwards so the starter points the right way.
The pan of the full crank utility is the wrong shape.
Old catcher steel bases had the stamping to be punched out to suit full crank or 4 stroke, then came the dimple for the power torque. Power torque is the same pattern as a 4 stroke.
Later steel bases are dual drilled for the side ways power torque or forward 4 stroke.
Its easy enough to redrill, just use the power torques tin flywheel cover as a template. And measure carefully using to make the center circles concentric. You could also use card board or ply or tin.
I do kind of like the engine facing back on a Utility, less things poking out the front to break. You can push it further under cars and the like.
Depending on what starter, if its riveted then you could easily move it to the right spot to suit where the engine faces.
