Boiled potatoes can typically be kept warm in a food warmer cabinet for about 2-4 hours before they start to lose their texture and flavor. It's important to ensure that the food warmer maintains a temperature of at least 140°F (60°C) to prevent bacterial growth. After 2-4 hours, bacteria can start to grow rapidly, increasing the risk of foodborne illness. If you need to keep the potatoes warm for longer, consider periodically checking and stirring them to distribute heat evenly, or transfer them to a slow cooker on the "warm" setting. Additionally, make sure to handle the potatoes safely to prevent contamination during serving.