In addition to the flight instruments, there are a number of other essential guages for monitoring the engine and fuel. You should be aware of their normal operating range, and their upper and lower limits.
The tachometer displays engine revs, and will increase and decrease with throttle changes.
The oil pressure gauge displays the pressure of the lubricating oil in the engine.
The oil temperature gauge displays the temperature of the lubricating oil in the engine.
The coolant temperature gauge displays the temperature of the coolant in the engine.
The voltmeter displays the state of charge from the alternator to the battery.
The fuel pressure gauge displays the pressure in the fuel system being delivered to the carburettor(s).
The cylinder head temperature (CHT) gauge displays the temperature at the cylinder head.
The exhaust gas temperature (EGT) gauge displays the temperature of gases in the exhaust system.