Wayne PC1 & PC2 pumps apparently use a smaller diameter impeller, listed as "Impeller dimensions: 1-3/8" Diameter, 1/2" Width D Shaped Key Hub for 5/16" Shaft" here;
https://www.amazon.com/Utility-Water-Transfer-Impeller-Replacement/dp/B06XDHJYVL/
There is still the possibility the whole pump assembly could be removed from the electric motor and adapted to fit one of these engines missing the pump unit, you would still need to make the shaft adaptor if the original was missing.
David