When you fill it...fill it through the little tank. That is, fill it through the line that goes to the carb...which will fill the hopper first, then the larger tank.

Little story...and an example of the use of the hopper tank. I got my kids a little .21 seaducer mono. It only has a single tank setup. Kid goes out...runs half or more of the tank out, then starts doing large sweeping left turns. Boat dies. I tell her don't do left turns in the boat like that. As teenagers do...she doesnt listen. She fills it back up and starts running all over the place. Gets down to half tank or less of fuel...does a large left turn, boat dies.

The boat is dying because the pickup for the fuel is in the left side of the tank. When the single tank gets lower on fuel, and you do a left turn (especially for a large sweeping turn), it starves the engine of fuel because the pickup is no longer in fuel. If her setup had a hopper tank in it...it would not have died in the left turns because even when the pickup in the large tank is not in the fuel, the hopper tank would have been totally full of fuel and it would have made it through the left turn.

Sean