I have a B&S Intek engine 33R877-0009 on my Ariens (Husqvarna) mower. It is 7 years old and has suddenly begun smoking (white) when under load such as in heavy grass or up a very gradual bank. Normal level ground mowing does not produce any smoke. The engine otherwise runs smoothly. Before I give in and take it to a shop for major repairs, I'd like to check the obvious things. I have checked the oil level and it is normal. They also say to check the breather tube to see if it's clogged. I can find the breather tube on available online parts diagrams, but I can't find it on the actual engine. I can't fathom how this tube could be clogged since it appears to be a significant diameter, but I'm willing to check it out, IF I can find it!