Yanmar 3GM30F not making full power

[Salty Possum]

It was the exhaust elbow. No black smoke so I kept going over the fuel system—plus that is easier—like the drunk looking for his car keys under the lamppost because the light is better. At least I got some of the 32 year old fuel line replaced. But replacing the exhaust elbow cured the problem. The old one didn’t look too plugged up from what I could see peering into it. The shop man that I paid to get it off the manifold actually had to cut it in half to get good leverage with his wrench—revealing severe restriction right in the bend. Know a bit more about my engine now.

[Wotname]

Thanks for the update, it really helps others when the final culprit is revealed.
Well done for getting it fixed.