i just took out the thermostats in my 2002 90 hp johnson... the seal that the t-stat seats on has sand particles on it, which leads me to believe there could be more inside. can i flush the motor w/out the t- stats to clean it out? thanks.
Yes, just leave the t-stats out and put the muffs on it and flush it good. You may want to remove the lower unit and check the impeller if you feel it's nessesary.