90206-001-000 Tappet Adj Nut - Overview. The 90206-001-000 Tappet Adj Nut is a crucial component within Honda marine engine systems. This adjustment nut is specifically designed for tappets, which are essential for controlling valve clearance and timing in the engine. By maintaining precise valve adjustments, the tappet adj nut ensures the engine operates smoothly and reliably. Engineered to OEM specifications, this genuine Honda part integrates seamlessly with existing hardware, delivering cons