Hi Robert:
First of all, recognize that I don't have Lewmar ports on my 1980 Hunter. But if yours are the opening kind and if the gaskets that have failed are in recessed channels, then maybe this cut-and-paste recount from one of my posts five or so years ago might give you a low cost and relatively easy to do solution. Of course you may need to modify the concept to your own situation. My ports are still not leaking five/six years after the described fix:
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" .... An inexpensive fix stopped the leaking and the fix looks like it will last. The plexiglass window ports on my boat are the type that swing open to the inside, hinging at the top. The original gaskets on the frame had become hard and compressed. What I did was:
- The original gaskets are affixed inside a channel all around the perimeter of the port frame against the which the plexiglass is dogged tight against. I left the old hard/brittle gaskets in the channel, but with a razor-sharp box cutter knife, I shaved these original gaskets flush with the outside of the channel.
- I then wiped the shaved original gaskets with lacquer thinner to clean off any dirt/grime/soap/wax and to "reactivate" the hard foam for the next step.
- I then applied a high quality stick-on gasket tape made by MD directly on top of the old shaved/cleaned gasket. (MD gasket tape is available at all hardware stores. Look for the smooth surface foam type -- not the porous foam stuff. It comes in a double band, and is hollow in the inside. The two sides neatly split when the two sides are pulled apart. Comes in brown and white colors.) An alternative is to go to your local auto store and look for self-stick window gasket products. Make sure that the two ends of the new gasket tape around the perimeter meet on the top side. Don't stretch out the stick-on gasket as it is applied.
- Dog tight and then open the port to check that the new gasket is aligned correctly.
- The self-adhesive needs pressure and time to really stick. So close and dog with moderate pressure the port. Leave for a while.
This solution might be worth a look-see for your situation. However suggest that you do only one port first to check if it works before doing the others. "
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I am a somewhat concerned that your PO used silicone sealant in a misguided attempt to address the problem. This because silicone is really tough to remove. And often, even for years later, nothing will adhere over where it has been. After you shave off the silcone, you may need to wipe many times with acetone before new self-stick gasket will stick. And even then, possibly it won't.
regards,