I’ve had two starters fail on my 150 e-tec in 3 years. One was dead pretty much out of the box. The second one died after the motor hadn’t been run in 6 weeks due to surgery keeping me off the water and the bendix shaft snapped when it went to engage. If a third starter goes, the motor will go too.
As for the original question, I have had two times this year where the motor didn’t want to start after having sat for a while while fishing. Seemed like it wasn’t getting fuel. After pumping the ball (the only two times I’ve ever had to pump it) it started fine. Leads me to believe I have an air leak somewhere, but who knows. Haven’t tried chasing it down because it only happened twice this year in about 30 trips out. If the engine is hot, it always starts.
Try pumping the ball when it won’t start and see what that does. Just an idea.