hello i i have a 1986 mercury 225 bridgeport outboard motor. i ran the boat all day and on the way in i was running half throttle and it just bogged down all of a sudden. now it won't go past 3000 rpm and it won't plain out. i replaced the spark plugs and it plained out for a second then it bogged down again. it sounds like it isn't running on all the cylinders. when i put it in nutreal and give it throttle , it spits and backfires. can someone please help with my problem...thank you
