Yanmar 2GM20F exhaust elbow

[wipe_out]

Hi,
Our Yanmar 2GM20F has an exhaust manifold with an elbow on the top turning through 180 degrees (see photo)..

How do you determine if the exhaust elbow needs replacing?

Do you typically just replace the elbow or the manifold section as well?

 

[black mercury]

To inspect it you need to remove it and look up inside. The manifold part is separate, it will unscrew from elbow.

 

[wipe_out]

The manifold part is separate, it will unscrew from elbow.

So is the manifold part not generally routinely replaced unless there is an obvious need to replace it?

 

[Topcat47]

The bit shown looks like the high rise water injection casting. In this case, mine is bronze. It screws into a transition piece which is normally just a domestic brass plumbing fitting and this is turn is screwed into a cast iron elbow mounted on the end of the manifold. Failure almost always occurs in the threads of the transition piece and the elbow.

My bronze casting is as good as new after some 15 years service but I"m on my third elbow/transition piece, as these typically last about 6-7 years.

These high level exhausts do not usually suffer from the failures associated with the ordinary exhaust fittings which typically cause head problems, but I check mine every time I swap the elbow/transition piece.