Hello Windy6cyl

A warm welcome from me to these great forums.

A good place to start every visit is 'Active Topics'.
However, getting use to the search bar at top is a great resource finder.

A Colt 4hp would be a Colt Minor.
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=67345

I hope your experience is rewarding.
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Jack