1997+ Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-826148R2, Page 21Get this manual
Flushing The Cooling System WARNING
To avoid possible injury when flushing, remove the propellerRefer to Propeller Replacement1R emove propeller (refer to Propeller eplacement)Install the flushing attachment so the rubber cups fit tightly over the cooling water intake holes
5C heck for ste ady stre am of water flowing out of the water pump indicator holeC ontinue flushing the outboard for to minutes, carefully monitoring water supply at all times
6Stop the engine, turn off the water, and remove the flushing attachmentR einstall the propeller
Storage
2Attach water hose to the flushing attachmentTurn on the water and adjust the flow so water is le aking around the rubber cups to ensure the engine receives an adequate supply of cooling waterThe major consideration in preparing your outboard for storage is to protect it from rust, corrosion, and damage caused by fre zing of trapped waterThe following storage procedures should be followed to prepare your outboard for out-of-se ason storage or prolonged storage (two months or longer)