Expansion tank exhaust and single cylinders, regular pops?

[casper ghost]

An odd question... My single vsh has a large expansion tank in the exhaust and I notice that under revs the exhaust "pops" are not regular, as though the engine is miss firing. Could this be the exhaust, or is it miss firing. When standing next to the engine it sounds perfectly fine, no sign of any miss fire..?

Casp'

[AndyV]

Am not going to be able to answer this as I don't know enough about engines but I can say that I have seen (or rather heard) odd effects that I assumed to be from the expansion boxes of exhausts. I have heard single hot bulb sound just like they should with your head in the engine hole but with a second pop from the exhaust that that could almost trick you into thinking it was a twin. My old Kelvin twin could on occasion (presumably an exact combination of revs and load) do a passible impression of a triple at its exhaust but sounded just as always stood beside it.

[MtB]

An odd question... My single vsh has a large expansion tank in the exhaust and I notice that under revs the exhaust "pops" are not regular, as though the engine is miss firing. Could this be the exhaust, or is it miss firing. When standing next to the engine it sounds perfectly fine, no sign of any miss fire..?

Casp'

 

 

Your VSH is a four stroke, yes? My two stroke Skandia makes a different sounding 'bang' on every firing stroke but the 4 stroke Kelvin is utterly uniform. No change at all in the sound of one firing stroke to the next.

[casper ghost]

 

 

Your VSH is a four stroke, yes? My two stroke Skandia makes a different sounding 'bang' on every firing stroke but the 4 stroke Kelvin is utterly uniform. No change at all in the sound of one firing stroke to the next.

Yeah, 4 stroke.. I expect it is misfiring, but I just can't tell when right next to the engine.. Work and holidays mean i'm not at the boat for a few weeks, but I will have to look into it more.

Casp'