considering the output of the motor and the setup im impressed. It is actually a hit and miss by the sounds of the description.. although a small one.
Its likely that its an industrial engine without a governor thats been used.
The use of a combined decompressor and spark advance is unusual for today but not then, since alot less of an engines systems were automatic if any.
It'd be an interesting project for someone to get hold of details of the motor and re-create it. I dont know of a motor company with the initials P-T though and through my father I know alot of the early industrial/farming manufacturers such as IH and others.
A really good find - I doubt Mr Patdevin had any idea that someone would be looking at his machine over 100 years later...