Need to replace my engine

[Bee Bop]

I have a 1999 ez go gas with a Robbins motor. I just got it a few month ago and it has been running fine. The starter went out so we pulled the engine to replace the starter. When we had it out we decided to replace all the seals/gaskets. We couldn't get the clutch drive assembly off, tried for two days (using an impact driver and various methods,also the correct tool) and no luck. I said **** it, and we put it back together. It then would start and drive at low RPM, but when you gave it too much gas it bogged down. I gave up and took it to a repair shop. They told me the compression was at 90 and had to be a minimum of 120. The robbins engine is discontinued, so I don't want to rebuild. What is the most inexpensive route for replacing the engine?...maybe a honda...but I don't want to lift it or pay $1200 for a plug and play mounting kit, plus cost of the engine....any suggestions?