Carb Question

I was out of the country for a year and packed up the boat. Full tank of gas, double dose of Stabile, ran the boat on the river for a small bit to burn out the untreated gas, fogged the carb and pulled the spark plugs to oil the inside of the cylinders. (as well as winterizing the rest of the boat) Then I topped of the fuel tank with more treated gas.

After about close to a year and a half, I put a new battery in and in cranked up on the first try. It ran smooth for a half a tank of gas. Idle through high end had been working well. At half a tank, it began to idle really low (dropped from 600 rpm to 100 rpm) and the engine eventually dies. It will start with about half trottle applied. Also, it began to hesitate on accelerations (both from a slow speed as well as from 30 mph)and will die almost immediatley unless I am quick to reduce throttle.

I continued to burn the remainder of the gas out (boat runs great at a steady speed if I can get in put in gear without dieing). I filled up with new gas, replaced the fuel filter, cleaned the fuel screen on the carb primary bowl, and replaced sparkplugs with new AL 24s. I am still having the same problem.

I didn't see signs of water or debris in the fuel when I replaced the filter. I have ordered a carb rebuild kit from SKIDIM and it should be here tomorrow.

Today while I was continueing to trouble shoot, I noticed that after pumping the throttle about 10 times, fuel was only under the port or passenger side primary throttle plate. Is this normal or should equal fuel be in both throttle throats?

Sorry for the long post. The boat is a '89 2001 with stock 351W (with exception of electronic ignition kit) It was a quick and sudden change that affects both idle and accelerations so I am thinking some debris or gunk build up is affecting the metering plates or needle valves. Thanks,