I had a 302 888 in a '75 glastron. Great engine, ...but to rule out anything...replaced almost everything. wires, plugs, points, cap, all of it. relatively inexpensive for good piece of mind. on my marathon (4 cyl, 165) did the same thing because the guy I bought it from forgot to pull the hull plug out before winter, filled with ice snow and water, corroded all the electronics. So for peace of mind, and to ease your hunt for the bad connection, replace the easy stuff. if you got it turned over, great..... compression, ignition, fuel.... keep it simple. its not rocket science. replace suspect wires. test lights and multimeters really help to figure out where the connections are broken. My best friend? Mercruiser manuals. Helped a noodlehead like me figure stuff out! good luck!