Merc 25hp EFI - Water Blockage

[Sugo]

(Model F25ELPT, serial 0r374682) With thermostat cover & thermostat removed as well as lower unit off I can't get water to flow up the water tube. One of the ports under the thermostat cover seems to be blocked as well, I suspect a blockage around the top of the water pipe causing the issue. Water nor air pressure will free the blockage from either end. A coat hanger up the water pipe reaches all the way to the block and sounds like its tapping the block. Any ideas were to start? power head off or alternate recommendation how to find the blockage? Other posts suggest the rubber grommet at the top of the water pipe imploding due to salt water, power head off to explore this theory or is there another way?

 

[Sugo]

No Title

Did not get any tips on this, however I did find and fix the issue. For the benefit of anyone attempting to fix the same issue here is what I had to do to fix it. Power head off, lower unit off, lower casing off. The blockage was salt build up in the passages on the bottom side of the transition plate that is between the lower casing and the power head. See picture. After cleaning out the salt, I also replaced the water tube and rubber grommet on the top end of the water tube. There was also salt build up under the grommet causing the grommet to push upwards restricting the flow of water adding to the conditions that caused this to happen. Gaskets for the job were not cheep, In the end, the parts cost me about $350cnd including impeller, as it was apart already. The motor is only used 4 times a month to cross a narrow channel, and lives on the boat in at the dock year round. Perfect conditions for quick accumulation of salt build up. I rigged a flush kit, dock side, that will hopefully slow the salt build up down the road.