The 750 should be a good fit for that engine. I would see if you can get the pump warrantied and try a new one without paying for it, just because something is new doesn't mean its working properly.
Maybe coil or ignition module, the duraspark boxes are a fairly common replacement item. Unless you have MSD, in which case you should check battery voltage when everything is running to verify a constant 10 volts to the control box, they don't like to work on much less than that.
If you can read this, thank a teacher. If you can read it while pooping, thank Bill Gates!
"A girls butt hole is like a 9 volt battery. You know its wrong, but eventually you put your tongue on it."