Wednesday, February 4, 2015

Workshop Wednesday-Leaky Boots

 No I'm not talking about wet feet.

 Whenever a piece of equipment comes through with a complaint about erratic idle, the problem can usually be connected to an air leak. Hard starting issues can also be attributed to air leaks. Some leaks are very small and hard to detect. Others are more obvious. This saw looks pretty normal at first glance.

Upon further investigation we find this:

 This intake boot is pulled away from the manifold adapter. This will cause a lean condition and also allow dirt into the engine.
 This repair is pretty simple and not too expensive. The problem is that we don't know how long it ran this way and how much dirt was ingested. It should be noted that these air leaks can also occur at the crank seals and the cylinder base gasket. It's also not often a leak is this big and obvious. Usually a leak big enough to effect engine performance is visually undetectable.
 The lesson to be learned here is that if you have a small two cycle engine that develops a high or erratic idle or is boggy and low on power don't continue running it. Besides possible dirt ingestion, the lean condition can eventually cook the engine and ruin it.
 Why am I posting this? Why not. It's a big part of what I see when working on saws. If you can understand the importance of a tightly sealed crankcase in a two cycle engine then you can become a better fix-it dude. And when it comes down to it, isn't that all we really want?



  1. Scott, I enjoy reading your posts because every once in a while there is some really good info that a guy can retain and use some day.I may be a little easier impressed than the next guy because i would be mild/medium knowledged on this compaired to a shop dude.My data rating on this with a 1-10 scale would be a ....wait for it...six- Tom S

  2. I'll take that six and promise to throw in a few 8's once in a while just to keep it interesting.