glenncal1
Active Member
We went out on the 1996 420 AC that we are looking to buy in the next week or so. The current owner runs the twin 7.4 Mercs at 2500 rpm. The ride at that speed is less than great. I would most likely run at 3000 which on that boat you are doing about 15 MPH. At that speed it doesn"t seem to wallow so much when dealing with any wave action. What speed do you guys generally run at. Yes it will drink gas pretty well but I dont usually go that far
That is the wrong engine speed to cruise at. Those motors should be run 32-3400 rpm for high speed cruise (on plane) or 10-1200 for a low speed cruise (off plane). At 2500 the boat is probably plowing through the water not quite on plane, pushing a lot of water and burning a lot of fuel. At full throttle the engines should be turning 42-4600 rpm, if not you may need to have the props checked and possibly tweek the pitch. You should run either on plane or fully off plane for the best efficiency.