Ok thanks for the info. I just fitted the repaired parts in and the engine runs as before. So the exhaust hole should actually be larger? hmmm, maybe that's why I can't bring up my rpm pass 3100 under load. Can't wait to get my hands on the new parts. BTW, the Mixing Elbow has reverse (left-handed) thread if anyone is interested to know. hence the joint has 1 side LH thread and the other RH thread. Sharks! my Yanmar dealer didn't even know this when I asked.
2002 Hunter 326, SV Millennium 2
1999 Macgregor 26X, SV Millennium