And so it continues......
My engine exhaust has a close nipple then a 45° elbow tilted upwards followed by a 4 inch nipple to the elbow. The 4 inch nipple is completely rusted out and snapped in two. We were unable to remove it from the 45° and the guys I called in to help me were unable to get any of the rest of the piping off. So after researching here on the site, I managed to get the manifold off the engine. (Nuts are 1/2" on my boat.)
But still bolted to the manifold are the heat exchanger and the raw water pump. I took it to a machine shop and he thinks he can pull the pipe off. The good news in this is the exhaust ports on the engine still look clean with no rust. So whatever caused the rest of the piping to fail did not reach the engine.
In a slightly unrelated note, I pulled the fuel sender unit from the tank and got a sample of the contents of the bottom of the tank using a hose taped to a stiff wire and a squeeze bulb for an outboard fuel tank. There was no water or crud visible in the jar or the clear hose. I was worried that the tank had been sitting for nearly 2 years and was heavy in agriculture.
