One of the least expensive, yet most effective grease cutters is Trisodium Phosphate. It's available at most big box hardware stores, sold as "concrete cleaner". It's a white powder that can be mixed with water into a brushable paste. Apply it liberally to a greasy engine with a disposable paintbrush, let it work awhile, and hit the engine with a pressure washer (hot water if possible). Be aware that it will soften or remove paint, so be prepared to repaint anything you use it on. I use it in a very hot water (not quite boiling) soak tank to degrease firearm parts prior to bluing.
https://www.ebay.com/itm/254741927305?Jerry
