Why would a Johnson gt 150 outboard motor get hot after aprox 20 minutes running?

A Johnson GT 150 outboard motor may overheat after about 20 minutes of running due to insufficient water intake for cooling, often caused by a clogged water intake or a damaged impeller. Additionally, low coolant levels or a malfunctioning thermostat can lead to overheating. It's important to check for blockages in the cooling system and ensure the impeller is functioning properly to prevent damage to the engine. Regular maintenance can help avoid these issues.