It does around here to buddy, so yes.
Dieseling is a known problem with specific known steps. You already did one, timing.
1. Timing
2. Idle screw set too high
3. Carb not shutting due to buildup on the carb/worn out
4. Carbon deposits in the head
5. Valve got a hot spot or stuck open, again deposits
6. Engine running too hot for another reason
The last reasons are related to pre-detonation, probably because of carbon buildup. So it gets too hot b/c too high compression, a hot spot forms in the combustion chamber and keeps igniting the mixture without spark.
So, you checked the timing. Then you check the operation of the carb. He already checked and sees the spark shuts off when the ignition is off, of course.
Then you either use a chemical engine cleaner to clean out the gunk, barring that, take off the head and clean it out.
Source: 10th Grade small engine shop