I have a 2000 model 70 hp 4 stroke that I had the lower unit replaced in. After running (trolling ) and running around for about 4 hours ( constant running) the engine ran hot. Towed back to landing and carried to shop. Mechanic did a vinegar flush and said engine was not worth fixing. There was water coming from the bottom of lower engine cowl area . It looked like the motor mounting pate area to me. Any ideas as to what the problem could be. There are no signs visable of running hot. Engine stills starts and runs and has 150 compression on all 3 cyl.