Engine: Jan 2007 Mercury Optimax Pro XS
Serial: 1B458912
Problem: Spitting and sputtering under load. When I load the boat onto the trailer it sputters and almost dies. On take off it will sputter and act like a vehicle does when it runs out of gas.
Two weeks ago, I took my new to me boat to the local Mercury mechanic to have the air and fuel injectors cleaned because I read that is good maintenance and upkeep. They called me that evening and informed me that I had a fuel leak and would need the diaphragm and tracker valve replaced. They also had to replace the spark plugs because they fouled those. I went ahead and said fix it to the tune of $1200.
I took the boat straight out and it was sputtering under load. Not horrible, so I thought maybe I have bad gas from the previous owner in the portside tank. So, I switched to the Starboard tank with fresh fuel that I put in and still sputtering under load. I fished for a few hours hoping the bad fuel would run through. Then I tried another trip and still the same problem.
I took the boat back to the mechanic and they told me today that they drained the fuel, cleaned the spark plugs, put a new O-ring on one of the fuel injectors, and replaced a cracked O-ring on the VST. Still the problem is not fixed. They said the fuel is at 90lbs and the air is at 80lbs. They are going to replace some plate tomorrow that I cannot remember the name of and see if that fixes it.
Can anyone give me some advice as to what it could be? The boat ran perfectly fine the first time I took it to them.