What is the make of the New engine? Model Type Code Serial? Was the old engine the same brand as the new one?
If the "New" engine came off of a fairly new mower it could be a few things. What color are the two wires coming from the engine? Red and Black or red and White? Two Black Leads? Do the leads go to a white 2 pin plug in/connector or a yellow 2 pin plug. in/connector. Please post answer and let me know.
Luggnutt
February 2012