The whole exhaust system on this boat was original, had never been changed. The manifolds looked very rusty underneath, and I thought I saw some smoke coming out of the manifold at the first spring start up. It turns out is may have been coming from a loose block drain plug on that side, it was barely hanging on by one thread, the block was wet there, and it came of with a turn of my fingers. All the seams of risers and elbows are full of rust. So it looked like time for complete replacement. I have only done one engine at this time, and may wait until fall to do the other.
So the parts I bought were all sierra, came painted on all surfaces. I sanded the paint with 120 grit paper on a random orbital, they looked nice after. The long studs coming off the manifold to the risers were dripping very slowly at first, one or two per side of engine. Also was getting a slow drip or two on the elbow bolts. Redid the gaskets again after that with similar results.
Gave up, took for a 20 min ride at 1400 rpm, spent overnight, came back, went home and then went back today. Torqued all bolts again, started up and ran to temp, and all seemed to seal up. Did not see any dripping from any places today!
I do not have those overflow reservoirs, that does sound like a good idea to add.
