Workshop Wednesday-EFI

 I reported a while back that Husqvarna has computerized some of their chainsaws. We can connect a laptop and check trouble codes, run tests along with viewing the running history of the machine. It is the future of small engines until something more environmentally friendly comes along.
 Your next lawn mower may be the same way. EFI small engines have been around a few years but I am first being exposed to them now as Husqvarna is using efi engines in some of their zero turn mowers.
 I do the 2 cycle engine repairs at the shop but I was volunteered to do the troubleshooting on this project. Partly because I had the time to load and learn the software and partly because I already had a laptop setup for running other shop software and partly because I like this kind of techy crap.

 The program for troubleshooting this Kohler engine seems very complete. We can monitor every part of the efi system, check codes, log data, set event triggers, access service manuals and so on. In this particular case the MIL (malfunction indicator light) was on but there were no codes stored. Turns out the system is very complete but can't diagnose every problem. For that we needed old fashioned common sense. If the computer says the engine is ok then the problem must be elsewhere. Sure enough, the MIL light had a wire pinched during assembly and was illuminating.

 In other news...the big talk in the shop yesterday was a high speed motorcycle chase. My work space is the closest to the road intersection and I could hear a loud sport bike coming down the road. As it turns out we had a guy running a back hoe in the yard and he heard the bike too. Pretty loud. The rider blew the stop sign and headed down the hiway. Pinned throttle through 6 gears for as long as I could hear him. The sound of the local cops siren finally drowned out the sweet sound of an inline four at full tilt. I have no idea how this story ends but I like that the "big news" in this small town is nothing more than some guy up to shenanigans on his bike.

Later.

Piston Lock

 People bring broken equipment into our shop everyday. Sometimes the equipment just fails. Sometimes it wears out. Other times the owner tries to fix it on his own and creates more problems. We are going to talk about one of those times. Not to belittle the guy that made the mistake. No, he feels bad enough. I just want to put this out there so anyone reading this doesn't make the same mistake.
 Before we get into it I need to post this pic of Al.

 I couldn't believe he let me take this pic so I of course had to post it. Things are slower in the winter and sometimes we have time to be goofy. I want to be clear, Al is NOT the person that made the mistake with the chainsaw.

 Back to our broken saw. The customer wanted to remove the clutch and do some repairs on the oil pump. To remove the clutch you need to prevent the engine from turning over so you can unscrew the clutch from the crankshaft. A popular way of locking the engine is with a piston stop. This could be a special tool, a stopper that replaces the spark plug or even a piece of rope pushed into the cylinder through the spark plug hole.
 Our guy tried something else. There was a note on the repair card about the customer using a skrench (that tool you get with some equipment that is a screwdriver and a spark plug socket in one) to hold the piston. At first I didn't realize what was being said but then it was pointed out that he admitted to putting the screwdriver into the spark plug hole, across the top of the piston and into the exhaust port. I'll try to explain better with this pic.

 Now certainly this will lock the engine. I'm sure he felt pretty good about his repair until he tried to start the engine. What happened?

  This is a look from the exhaust port where the screwdriver was sticking out. You can barely make out the dent on top of the piston.

 Here you can see where the screwdriver crossed the top of the piston. The burr created from the screwdriver jammed in the port and the pressure applied when removing the clutch created a raised edge and then this scoring. Now the piston ring is seized in the groove and can't seal very well to the cylinder. The engine only develops 90 psi compression and that's not enough for the engine to run.
 This saw will get a new piston and cylinder. A costly mistake that you will never make.

End.
 

Workshop Wednesday-Service School

 So yesterday at work I wasn't at work at all. Al, Greg and I traveled down to Milwaukee to Husqvarna service school. We attend these seminars annually to hone our skills and find out what new things we can expect to see from the largest outdoor power equipment manufacturer in the world.

  We tore apart some new chainsaws, discussed troubleshooting techniques and went over some service bulletins. Fun stuff.

 It looks like there may be some new George Jetson kinda things coming our way. Possibly bluetooth or wifi diagnostics from a smart phone. Husky already has chainsaws with "autotune". These saws have a micro processor controlled carb that can be hooked up to a laptop for diagnostics and firmware downloads. This technology will soon be found in string trimmers, blowers and other handhelds.
 It was kinda a drag falling behind a day in my work load at the shop but the seminar was worthwhile. I learned some things I can use every day, got a free lunch and won a hat for correctly answering a question. Ahhh, livin the dream.

End.