I am new to engines but I am very mechanical inclined so try to bare with me.(long story long) When we were out the boat would surge around 2600 rpm and would die when coming to a stop. We got home let it sit for a couple of weeks, tried to start and it would not stay running. So we rebuilt the carb. Now it stays running but the surging is now between 1600 - 3200. You are saying to obviously 1. check fuel pressure. 2. Change the fuel filter and check the anti siphon valve. How do you check fuel pressure and what is the anti siphon valves function.