Yanmar, factory assembled, no exhaust manifold gasket!

[boden36]

Have been experiencing increasing fuminess inside the boat and had been unable to find a cause.
In desperation I removed the heat exchanger and found no gasket between the exchanger and the block.
We have had the engine since brand new and this is the first time the exchanger has been removed so it must have been missed out during assembly ( the manual shows one in the exploded view)
So, if you are experiencing excessive exhaust smells from a Yanmar 3JH2 this may be a place to look.
It has been like that for over 1000 hours, so I guess we are lucky not to have died from the exhaust fumes!

Regards,
Richard.