tip for cleaning dirty engines, before using expensive gunk.
use whiie spirit in a skoosher bottle, the plastic type you Nan uses to water her plants, you might want to be carefull of some rubber parts and any hand painted bits, (I'm not so carefull and have never had a problem), work it into the greasy dirty corners with a stiff paint brush & leave it for 10 mins before cleaning off with rags/water/stiff brush or whatever is easiest for you
wash it off, finish any stubborn bits with your expensive cleaner.
Richie