Has anyone attempted and been successful replacing the casting plug behind the engine mount on a Starboard PCM 351W in a Mariner without entirely removing the engine? Got her in the water over the weekend and when I got her running I noticed it was weeping out pretty good, I got one of the rubber temporary plugs just to get her off the wall and into our slip. When I went to give it a tap to get it out the drift went through like it was tin foil. The mount is so close I could only fit the rubber plug itself without any of the plate/hardware with it. That being said it makes a pretty little stream when running. No water in the oil . Thinking if I remove that headbanger cockpit floor I might be able to gently support the engine from above just enough to move it above the mount or pull the mount from under it to access the plug. If anyone has had any luck with this contortionists act please let me know. Yes I ordered a complete set of brass to replace it and any other even remotely showing signs of distress.
20220529_120030.jpg
You do not have the required permissions to view the files attached to this post.
You can take that engine mount off without removing the engine. Just loosen the main adjusting bolt, making note of exactly how many turns you loosen it. You just have to loosen it enough to take the weight off of it. Loosen the bolts holding the mount to the block and when it starts to wiggle you know you loosened the adjusting bolt enough. Then remove the mount from the block, pry out the old plug, tap in a new plug (coating the outside edge with sealant) and put the mount and back and return the adjusting bolt to the initial position. Tighten everything down.
You can wedge something under the engine to hold some weight, but if the engine has FOUR engine mounts the other three will hold it in place while you have the one removed.
Just a quick update, Moving the mount did the trick to get better access in there. Ended up changing 3 plugs after going through and inspecting the rest just to be sure. It's also MUCH easier when the entire compartment cover is removed. Which has now become another project since seeing just how badly it was delaminated and rotted internally.
. Thinking if I remove that headbanger cockpit floor I might be able to gently support the engine from above just enough to move it above the mount or pull the mount from under it to access the plug. If anyone has had any luck with this contortionists act please let me know. 
Sponsors