Will a muffler hole cause back pressure & blowby ?

[Dennis]

Just realised I had a sizeable hole in my B7100's lower muffler. Is this likely to cause back pressure and explain blow by from the rocker cover ventilation pipe?
The tractor has done maybe 3000hrs but still starts first time and is not going through any oil.Just a lot of blow by......

 

[freewheel3]

Just realised I had a sizeable hole in my B7100's lower muffler. Is this likely to cause back pressure and explain blow by from the rocker cover ventilation pipe?
The tractor has done maybe 3000hrs but still starts first time and is not going through any oil.Just a lot of blow by......

No. If anything, the hole in the muffler would cause less back pressure, not more. Excessive blow by is a sign of a worn engine but all engines will vent a bit. If you're not using an abnormal amount of oil, it starts good and sounds alright, don't worry about it but keep an eye on the oil consumption.

 

[Eric McCarthy]

Mine fell off a couple of years ago on my B6100 and I've never noticed any difference in performance, didn't even seem to get louder either. I just have a 45 degree elbow nub.