Jason, if you go to this website, Amsoil makes four different marine oils, one appears to be for 2 cycle snowmobiles, motorcycles, personal watercraft, ATVs and jet boats, one for racing for short periods of times, another for DFI outboards, and the last is Saber, which is their standby 2 cycle outboard motor oil. I have never used Amsoil because my RPMs have been limited to 5,300 to 5,400 for short periods of time. Dr. Frankenmerc does not say which type of Amsoil he means, but I bet it is the Saber. Amsoil says that Saber can be used in 100 to 1 ratio, but Dr. Frankenmerc would use it at 50 to 1 or 40 to 1. He also mentions Mercury semi sythethic, which is the Mercury Premium Plus, which I use in a ratio of one pint to 5 3/4 gallons of gas.
http://www.amsoil.com/storefront/synthetic-powersports-boat-oil.aspxIt is interesting that he recommends only timing of 20 degrees before top dead center, as my Mercury's decal on the motor says 23 degrees. The thought is that with aging motors with carbon deposits, worn rings, crummy gas, to error on the conservative side - 20 degrees BTDC. A blow to performance but a plus to the engine's life.
Seafoam is a solvent that can be added to the oil, gas, and sprayed into the combustion chamber to dissolve carbon deposits, which build up on the top of the pistons and in the rings and cause damage because carbon retains heat and can prevent the rings from expanding.