Replacing Port Side Raw Water Pump

[k9th]

As most of you know, I am relatively new to the forum and a new Trojan owner having purchased my '79 Tri-cabin late last fall. This is my first time owing a boat of this size and I have never done any mechanical work on an inboard.

I am going to replace the raw water pump on the port side Merc 255 engine. I have never done anything like this before and want to make sure I get all of the needed sea cocks closed before disconnecting the hoses. I am also going to add a blocking plate and appropriate gaskets to the manifold on that same engine.

Can someone please tell me which one(s) need to be closed off?

[David Kane]

On my '75 tri-cabin, when I changed my port water pump last fall, I just traced the feed hose back to the seacock. The seacock is outboard of the engine's back side (remember the engines are turned backwards), or about 2 1/2 ft. in a forward direction from the pump & a little more outboard.

[k9th]

My engines face the bow of the boat and are located under the salon floor. I think that you have a V-drive with your engines under the aft cabin floor - correct?

The raw water pump on my engines mount to the outboard side of the engine and is attached by brackets to the block and driven by a single V-belt.

[aaronbocknek]

for you tri cabin owners.... david, on your design, where the engines are under the aft port and starboard bunks, the shaft is connected to V-drives and are installed 'backward' of normal installation. k9th, with the new design change that took place in late 1978, the engines were relocated under the salon in the more traditional installation and the shafts are connected to a velvet drive transmission and the shaft is longer. look for the water intake hose to run from the engines water pump to a sea cock that is towards the keel. it should be just one sea cock per engine.
hope this helps.
aaron