There are two mainstream fule addititves/cleaners out there. One is solvent naphtha, aslo called stoddard solvent, that is used in most carb/injector and combustion chamber cleaners such as Seafoam, MMO, Gumout, STP, etc. Seemingly the more active or effective solvent is polyether amine in "stronger" full fuel system and combustion chamber cleaners highly concentrated in additives such as Gumout Regane, CRC Marine Fule System Cleaner and Stabilizer, STP Complete Fuel System Treatment. many people in the marine industry swear by Seafoam, but all it is is really jet fuel with 10% solvent Naphtha. can some enlighten me on the effectiveness of solvent naphtha and polyether amine as fuels system and combustion chamber cleaners??