How do I remove the RTV from the oil pan opening that was used to seal the old dipstick to the pan? I need to take this off so I can re-seal the new dipstick tube to the old pan. The motor is in the boat so it's not too easy to get to the opening in the pan.

There is an O-ring that goes onthe dipstick tube before the RTV.

We use a sharp drill bit and just hold it in your fingers and turn by hand. DO NOT put it in a drill. Just turning it by hand will cut the RTV loose and the flutes on the bit should walk the pieces of RTV right out. As BIG Jim mentioned, there is an O-ring in there that will probably be useless if it's covered in RTV. We will just run a nice fat bead of silicone just under the little flare on the tube that seats in the pan. When you push it in, the silicone will ooze out and fill the rest of the hole. I'll then run around it with my finger to smooth it out and to be sure everything is covered well.
Eddie

depending on which RTV or silicone we have had luck with Ammonia, carb cleaner, brake cleaner, acetone or lighter fluid to soften it up then it will peel away atot easier. .Take a rag, soak it with one these and wrap it around the RTV for a while or spray it real good then let it sit. If you really have a nice paint job and do not want to jack it up, I might only try the ammonia very lightly.

Thanks for all the responses. I tried Xylene and MEK last night on the old tube to see how that would work and it did not work that well. It just might take me a lot of time. I think I just have the black RTV permatex that they sell at autozone. I'll try the other chemicals mentioned above - Thanks Bup. I'll try the drill method to remove the RTV on the inside - Thanks Eddie.