i have a 2000 25 hp johnson electric start non-tiller outboard. last year the overheat alarm went off and i called johnson tech support and they said it was most likely a blockage. the boat is used in a bay in maine where i have a lot of seaweed close to shore. its not used that much, its at a vacation home, mabey 10 hrs at the most a season, otherwise its stored in a garage during the winter months. i've never had any work done to the motor but i suspect the waterpump impeller is shot. overheat alarm comes on after about 15 minutes of use, but there is water coming out of the hose. a stream, but not that good of a stream. is it a big deal to change out the impeller in the lower unit? thanks....
