I have a 1983 Grady White Trophy 259 with 2 OMC 2.5L Sea Drives. I bought the boat in December not running, figuring on a bracket and repower. After repairing both starters, and replacing one starter solenoid and 3 batteries, I ran a compression test. Compression was between 98 and 105 psi on both motors so I decided to work with what I had. I like the Sea Drive, though parts are very hard to find, but the engine part numbers match up with Johnson. My problem now is I have the port engine running with ears, but after about 5 minutes the overheat alarm goes off. The engine temp gage shows 160 degrees. I pulled both thermostats off, left the covers off and started it. There is no water flow. A lot of sand/salt came out. I pulled the head covers off, and there was very little buildup in there. I have already installed a new water pump and housing. According to the coolant flow diagram in my factory service manual, coolant flows through the pump, up the tube, into the bottom of the exhaust cover, up through the exhaust cover, back down to the bottom of the block, up the cylinders then down through the head covers. My question is could I remove the lower unit and use a garden hose to try to clear the blockage. I don't want to pull the exhaust cover because I broke 4 bolts in the starboard cylinder head cover and I don't want to chance doing that again. All help is appreciated.
