1989 Wellcraft 233 with Mercruiser 350 with an Alpha1. Have had the boat for two years. Less than 300 hours on the motor. Started having trouble this season with it stalling at WOT after the boat has been running for 30-40 min. Once this occurs and the boat is back on plane, it starts and will run just above idle, staying on plane (flat). It has been enough to get us back to the dock on the past two occasions. We inherited the gas that was in the tank from the prior owner and have not run it dry since we have had it. I am wondering if this sounds like a fuel line blockage, water in the fuel, fuel pump or something else. Kind of happens when the engine is hot/warmed up. We ran it wide open/high speed from the dock for about 25 minutes, then idled around for a while and anchored. Boat sat anchored for about 2 hrs. Ran it at 75% for about 15 minutes then engine stalled. Started when flat, ran the boat slowly (flat) to get us the rest of the way to the dock. Both times so far were at night coming back after being out for a while. Engine is running fine at high speed and then sputters/jerks a few time abruptly choking the engine. Sometimes can prevent the stall if throttle is backed off enough and boat gets on plane (flat). Any advice is much appreciated.
