Husqvarna 555 autotune no spark.

[Hankoppotomous]

Have a 555 autotune that wouldn’t start after sitting a year or better. Shop stated it needed a carb but they couldn’t source one. I found one online through a parts dealer and got that replaced. Tried to start the saw and no go. Checked for spark and don’t have any. I’ve gone back over all my work but I’m at a loss. Is there any way to check the coil? I don’t want to just throw a $120 coil at it as it also appears you need to fully breakdown the saw to run the wires up to the carb.

 

[Bob Hedgecutter]

You are speaking way to modern for me- I do not own a single autotune or mtronic type of saw.
But, the whole idea of these new modern saws is there is a module that controls the tuning- so Im guessing module is matched to carb and if you replace the carb the module needs to be "told" you have done so- I am also guessing that it has to be plugged into a dealer laptop to do so?
Now if you bought some kind of Amazon special carb on the cheap- you might be on your own to try and solve it.

Like I said, I know next to nothing about these saws and ifing the module not recognising the carb will stop the spark at the plug- hopefully someone more modern and smarter will show up and provide the correct information.
@huskihl ?

 

[Stump Shot]

The only way to just change a carb on one of these saws is to put one on with the exact model number. As updates happen and new versions replace old this will not work until it is taken to a dealer that can hook it up to their computer and give it the new parameters and updates to work with.

 

[Fabz]

If new carb is a different version than the original then it will tell the coil NOT to fire. You can put the old carb back on and test for spark

 

[huskihl]

Set the coil gap to .010” and pull the starter over harder/faster and see if you have spark. The autotune/mtronic saws need a little bit tighter gap and need to be pulled over faster

 

[Fabz]

The 555 manual lists the coil air gap as .3mm + - .1mm as acceptable. I use my business card which is .012 or very close to .3mm. Never had an issue with any saw at this setting (.012) mtronic/auto or conventional. If the guy replaced the original carb with another and no spark ️ then I would check spark with the original carb connected. Really should be a stop/drop and swap on the carb but unfortunately Husqvarnas’ autotune may not “recognize” the signal from the new carb and therefore go into a no spark condition. Kinda sucks but this is “progress”

 

[Hankoppotomous]

Thanks for the replies fellas, looks like it’s off to the shop to be programmed.