last year I rehabed an old steel boat with this engine hadnt been run for three years. number three cyl. is low comp. I had the electrical panels? replaced along with plugs and carbs rebuilt and new fuel pump. It starts good and idles fine but under way it has no power and surges for about 1/4 second it will start at 9.5mph and ratchet up to as much as 14mph. then back down to 9.5mph. last week I had it out and out of nowhere it it went from 9-25!!!!! but only for about 15 seconds then back to 9.5mph. HELP I WANT TO GO 25 AGAIN! fuel tanks and hoses are all new.