I would check the carb setting before you start swapping fuel tanks. I have owned over 30 different nitro models though the years and have NEVER had a fuel tank flood the exhaust unless it was flipped upside down. The nipple for pressure is in the top of the tank....there is no straw going down into the fuel on 99.99% of tanks for the pressure..... if it was some how sucking fuel out once the level went down it would stop. But hey, it is your money do what you want but I HIGHLY doubt it is your tank. Not only that if it was sucking fuel out of the exhaust it can't ALSO send fuel to the carb. If the engine is running... you are NOT.... I repeat NOT "Sucking" fuel out through the exhaust. Where would the air come from to prevent a vacuum from forming in the tank if you had fuel simultaneously going out the pipe and into the carb? Can't happen, basic physics proves that wrong.....check your needle settings and engine temps.