How do you change impeller on johnson115 hp outboard 1982?

To change the impeller on a 1982 Johnson 115 HP outboard, first, ensure the engine is off and cooled down. Remove the lower unit by disconnecting the shift linkage and unbolting the lower unit from the midsection. Once the lower unit is detached, take off the water pump cover and pull out the old impeller, replacing it with a new one, ensuring the key is in place. Reassemble the lower unit and reconnect everything to complete the process.