A little more details for you, yes indeed it is a 4 cylinders single acting approx 5/8 bore x 5/8 stroke (2.5 cc each) with piston valves, and it self starts. The flash coil is 1/4 inch dia with 3/16 bore and 316 grade stainless steel. More pictures of progress as I put it all together
And the boat it all fits into...