Mercury - Service Monitor Engine Hour & Warning Indicator 79-8M0050399. OverviewThis Service Monitor is a simple way to keep track of engine hours and maintenance intervals on most Mercury outboards and gasoline MCM/MIE engines. It replaces older versions with a universal-style unit that installs cleanly and works the same across a wide range of setups. On the water, it gives you a quick way to monitor run time so you can stay on top of routine service. Sold in a Quicksilver clamshell package fo