Prop shaft strut leak - 04 210 LTD

[OzEmu]

Gday all,

Had the boat out a few days ago and noticed more water than normal being pumped out of the bilge, especially when underway (meaning more water coming in at that time). It was a few litres (a gallon or so) every time I turned the bilge on and I wasnt towing skiers.

I pulled it out and drained the bilge, properly by lifting the trailer hitch up high. I then put the bung in and put the hose into the bilge, filling up the bilge to check for external leaks. This is what I found (see video).

I will today put it back in and test for leaks around the flange nut / packing where the shaft proper throughs the hull.

I’m looking for advice, opinions etc on how easy to fix and bad this problem may be.

It’s a long weekend here, no servicing for a few hours away and a marine mech who saw this video said he has previously seen this on a G21 who had rotted fibreglass in that spot (finger crossed this isn’t the same for me).

Thanks as always.

[Jonny Quest]

That looks like silicone around the strut. Not good. Someone has tried to fix a leak without doing the repair correctly. Typically, the strut is bedded properly with 3M 5200 sealer/adhesive. I've not worked on a G21 but I'm assuming that the strut bolts might be a bit hard to reach, correct? Are you the original owner? If not, was there any previous damage at the strut? Has the strut been previously removed? When did you last perform a shaft alignment? The goal is to determine if there has been any strut movement, damage or improper strut positioning.

In my opinion, the "right way" to repair this is to re-bed the strut. That means removing the strut bolts and examining the fiberglass and strut condition and how the strut was bedded. Remember that shaft alignment starts at the strut. Some have used a laser pointer or a rifle bore sight tool to do this. If the strut needs to be "tweaked" just a bit, you can use a thin stainless steel washer. I would not use more than 2 washers at any location. Once the strut alignment is good, then re-bed the strut using 3M 5200 (including bolt holes). That should properly repair the strut and eliminate those pesky leaks.

JQ