It's a real smooth hard material. It's not JB Weld or similar epoxy. I thought someone may be aware of a material that is made for these type repairs. This stuff has been at work for 20 years, but I'm not big on glues or similar as others have said.
I'm going to guess MarineTex, which is a strong, well regarded epoxy that's been around for a while. Normally it's white or gray but can be colored. I'm guessing the oil made it brown. that info is worth exactly what you paid for it. If it isn't leaking, I'd run it as is unless you are going for big HP numbers. Figure a couple hundred bucks to weld whatever is underneath that if you can find a guy to do it.
