Sierra Thermostat Kit Mercruiser 18-3650 by Sierra International $24.20 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Sierra Thermostat Kit Mercruiser #18-3650 Includes: Thermostat Gasket O.E.# 27-47590-1, Thermostat: O.E.# 59078