Originally Posted by blakekrone
So the boat I bought in CA probably never had its drain plugs removed and I had to remove them last fall to dry block the engine before having it hauled back to MN. I went to put back in the plugs today and 1 side went in without any trouble, the other side however doesn't seem like it wants to bite at all. The plugs themselves look a little rough around the edges so I picked up a new 3/4" NPT plug and that won't even bite either. It looks like the manifold was so rusted out that the threads have deteriorated to nothing for the first few turns. Is it worth it trying to rethread with a tap or do I just need to get a new manifold?
Look for a 3/4" tapered plug or fitting. If that won't grab, go one size up, maybe metric. If it won't grab a new plug, re-tapping won't work because the tap is the same size. You could also install a brass barb fitting on both manifolds (use JB Weld on the stripped one), so you can use the hose & coupler they added to the boats in about '98. It makes draining a lot easier and the fittings in the manifolds don't have to come out.