[homemade87]

Most all marine engines run from 155 to 165 temp . They are designed that way because of the stress a marine engine runs ( like pulling a loaded trailer up a steep hill non stop ) . 180 is to hot . Remember the coolant is not only cooling the engine but also the exhaust system . The marine electronics is designed around 160 degree temp . You start pushing into the 180,s and most likely see some detonation . I would suggest you run the highest octane gas you can fined also .

In case you are new to this there is a fresh water impeller in the lower out drive that needs to be changed( I change mine every 2 years) . It has rubber fins that will come apart( need to find all the pieces if one comes apart) and leave you stranded or a burned up motor if not caught in time . Check out utube , you will see what I am talking about .