1988 evinrude,70 h.p. <E70TLCCA> SERIAL NO. <G1753065> power trim, keeps going up,will not go down,had to unhook power to get it to stop.afraid it was going to burn somthing out.I am not a motor kinda guy but can fix if it is simple,like replacing a relay or somtin.where to find relay will help to start with,any place i can go to get instructions on how to do this . or how to test to find the problem. thank you very much,rbass57.