Sounds like fuel starvation. You mention the engine was new last year, as in new to you or new as in out of a box, PDI new?
If the fuel bulb isn't going hard, then the internal diaphragm might have failed. That's unusual for a new engine. Tohatsu will still be under warranty so speak to the dealer.
If its new to you, then I can recommend a Quicksilver fuel primer bulb. Ensure the tank is properly vented. In addition, double check the fuel hose where it connects to the engine. Sometimes the rubber 'o' ring in the female connector dislodges (more aftermarket than genuine a Tohatsu) so restricting fuel flow. The stainless steel parts do seize given the salt water environment, so clean off and lightly lube with a little marine grease.
Lastly if you're worried about water in fuel, get an external fuel filter fitted. The filter on the engine is fine for contaminants, but won't stop water getting in.
Keep us posted as to how this is resolved.