Yanmar 3YM20 Exhaust Elbow Nut Size

[exfinnsailor]

Looks like a job for Friday . Remove . Clean . Get welded . Living miles from the boat anyone know what size the nuts are ? . Don't really want to take a whole tool box for 4 nuts ..

 

[mcanderson]

I'll be on my 323 on Saturday and can let you know then if this helps.

 

[steve28]

when you get it welded make sure they use stainless materials. also in all the people i have seen with this external elbow failure is caused by the exhaust pipe being a short run and very ridgid so in effect the engine bouncing on its mounts finds the weak point which is the thin weld on the elbow.

hope this makes sense, a remedy to this happening again is to use a silicone flexible exhaust joiner like the ones from halyard.

steve

 

[vyv_cox]

On anything else I would say it's 13 mm, a pretty standard size for most manufacturers. However, for reasons best known to themselves Yanmar mostly substitute 12 mm.

Personally I would take my whole tool box. These minor jobs have a habit of escalating.

I agree with Steve28 that this appears to be a fatigue issue. Other than his solution it would be worth trying to get some additional bracing to the elbow, maybe by wrapping the pipe adjacent to the flange with another layer.

 

[oldsaltoz]

We have a set of Metrinch spanners/sockets on board, they fit imperial and metric fastenings, anything to save weight on a cat.

Good luck.