Mercury - Quicksilver Throttle Position Indicator 2-Stroke Performance Series OEM Assembly 8M6005165. Overview. When you spend your weekends running shallow rivers or stretching out the throttle on open water, you start to appreciate the little components that keep your engine perfectly in sync with your hand. The Quicksilver 8M6005165 Throttle Position Indicator (TPI) is one of those small but essential parts. It's the quiet link between your throttle input and the engine's response, letting yo