V2403M engine knock

[r311terry]

We have a Jacobsen R311 mower with a Kubota V2403M diesel motor. Last fall cyl 2 failed. Just got it back from overhaul and it starts fine but develops an upper engine knock around the number 4 cyl after about 30 seconds of run time. Also there is a cast iron block/box in the exhaust system where the exhaust manifold and the exhaust pipe meet, what is this.

 

[kuboman]

We have a Jacobsen R311 mower with a Kubota V2403M diesel motor. Last fall cyl 2 failed. Just got it back from overhaul and it starts fine but develops an upper engine knock around the number 4 cyl after about 30 seconds of run time. Also there is a cast iron block/box in the exhaust system where the exhaust manifold and the exhaust pipe meet, what is this.

You will have to supply a picture for the exhaust question. As for the knock from the engine it could be a bad injector, a valve badly out of adjustment or a poor overhaul. You will have to do some investigation to determine which it is.