Wednesday, January 29, 2020

Playing Detective

 So this post was just gonna be some random pics from my phone of life at work. The more I scanned for shop pics, the more I found pics showing the results of detective work I've done to find running issues with chainsaws. Lets see what we've got.

 Here is a common one. Someone will come in with a saw that floods itself out. I'll rebuild the carb and when they get the bill they bitch because they claim they just rebuilt it. I state that I know it was just rebuilt because whoever did it screwed up and then I show them why. Sometimes its gaskets installed wrong but many times its because they didn't clean the protective coating from the rubber tip of the new needle valve. In the above pic, if the needle were clean it would be completely orange. "Well it was actually my brother-in law that did the work, I'll have words with him". Ok buddy, whatever.

 Two pics above, the intake manifold on the right and the cylinder on the left. I really wish the owner would have told me he put on an aftermarket cylinder before I had to figure it out on my own. He would have saved some money in labor costs. This case is something I see a lot. People pay for parts and spend time trying to fix it then bring it to a shop and pay to have someone else fix it the right way. This guy didn't save any money buying a chinese cylinder and ended up buying a new factory cylinder anyway. In the pic above you can see the port is too big and the lip of the seal hangs in the opening of the port. This creates and air leak and a lean condition that would eventually ruin the piston and cylinder if not caught early. Pro tip: if you have an unusual high idle condition and a saw that will rev really high but has no balls in the cut then shut it down and have it looked at. It most likely is running lean.

 Above is another example of an air leak/lean runner. This plastic intake manifold isn't something that a person would normally remove and look at. Because the bolts were tight and the plastic isn't warped along with this being a newer unit, there is a fair chance this came from the factory this way. While a company can have a good reputation, it is still made up of individuals that can make mistakes.

 In the above pic you can see a rubber intake boot on a concrete saw is not seated properly. It was replaced by a shop mechanic that usually works on large equipment. He was so close to getting it right. I don't think the owner liked paying his guys wages to fail and then pay us to figure it out because we get a lot of small engine work from them now.
 Most of the time these types of air leak problems are found by doing pressure and vacuum test of the crankcase and then searching for the leak. Sometimes even when you know where the leak is, it still takes some figuring out why. Factories want to know why for warranty claims and people want to know why so they can blame someone else.
 I enjoy playing detective and its a nice break in the action between the broken starter recoils, oil leakers and dirty air filter tune ups.


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