FD-10S exhaust loading tube question

[defoucault]

In the process of cleaning the carbon off the exhaust port area and noticed the 376289 Exhaust Loading Tube Assembly. Since I did not know a thing about this I removed it and noticed that both these tubes where plugged with hard carbon deposits. I dug all the carbon out and cleaned the outside. My question is how are these tubes working and what is the consequence of having them plugged? Engine overheat? Engine power loss? Is there any diagram of the exhaust fumes travel available anywhere?