sort of thinking ahead here. got this spare engine?? other than get it going, and that probably would not be all that difficult, but some expense involved. What would you all do for the criteria that says rebuild. compression? all four cylinders within 10% of each other and between 105 and 135lbs?? add oil pressure to the mix ( but that means running??. or just jump in with both feet and start tearing it down?? tearing down not that big a deal, then block and head dipped,??? comments. Now the last engine i rebuilt was a 30hp Kubota,(great motor) and i literally had book in one hand and wrench in other. when i sold the boat the compression was the same as when i launched the rebuild, can not say enough about that kubota engine