The 6125 SFM design lends itself to reasonable maintenance costs because the timing gears are at the front of the engine. No need to detach from the marine transmission during in-frame rebuilding at the end of its service life.
MER sells engine repair kits that include cylinder kits (with pistons and rings loaded), gaskets, rod and main bearings, and new connecting rod bolts. With a rebuild kit from MER, a spare cylinder head, and a water pump, the engine can be easily rebuilt "in-frame" in a very short time.