Husqvarna 550m2 xpg new coil problem

[openspaceman]

Way too modern for me with lots of electrickery I don't understand but a chap I used to help out has dropped off this saw which won't run.

 

He did not explain why he decided to put the new coil in, the previous (OEM?) one is just black and marked walbro.

 

I wonder if it is the right coil as the plug lead is a very hard and tight fit. @adw?

 

Spark is weak and the picture is taken with the coil gap at 0.4mm and near enough TDC. It does not fire at all even with the new plug (he did not bring the original plug) or with petrol spray in the intake.

 

I see the heated handles seem to use the power off the coil pick up instead of a separate alternator mounted under the flywheel like the old type??

 

Any other thoughts?

 

Is this a case of needing to set something up on a diagnostic port?

 

[spudulike]

In short, I think you have the MK1 coil on a MK2 machine.

Mk 1 PT No is 581 72 36-02

MK2 PT No is 582 77 74-01

The programming only happens when you change the carb but the firmware of the autotune in the carb should be matched to the coil part number as the CST (Customer Service Tool) will ask when updating.

I think your Part number on your coil starts with 581 but it is difficult to read but am taking this to be the MK1 part code.

I don't know if the MK 1 coil will work with the Mk 2 flywheel - probably not.

I don't know why the coil is marked "Walbro" as they manufacture carbs and most Husqvarna coils are manufactured by "SEM"!

Fit the old coil back, close the gap right up and see if it sparks and check in subdued light...it won't be a big fat spark but will be visible. If no spark, fit a new coil of correct type.

My belief is the AT and heated handles get their EMF from the power generator behind the coil.

I am sure ADW will fill in the gaps if he can wrench himself away from Sanditon....now Downton abbey has finished!!

[Dan Maynard]

That does look like you could measure the coil gap with a tape measure!

[openspaceman]

Thanks @spudulike I did think there was a reason the plug lead was a bit short.

 

The part number of the blue coil is 518723602 so mk1

 

will refit the old coil as you say and report back

[adw]

So the mk11 coil is a Waldro unit and is black, you can also tell because it does not have a separate earth wire, the two units are not compatible, the part no.s on the coils do not match part no.s in the Ipl because it is supplied complete with the wires and wire cover, the cover is also different as it clips too the edge of the crankcase unlike the mk1 which is held with a self tapping screw, also the heated handle model Should still have a generator behind the flywheel, there is insufficient power within the coil to work the handle heaters. The mk11 coil can and does bare the wires and short out just as the leave the crankcase to the carb so take a good look in that area. Coronation street just finished Steve.

[adw]

Forgot to say the 550/560 Mk11 now has the same sealed bearing both sides, they are quite prone to the flywheel side seal leaking, this makes it difficult to start, and takes a long time to return to a fast idle, when plugged into CST the L setting will be down to 10 or lower so jet wide open to try and compensate for the air leak. Still like the Mk11 thought.

[openspaceman]

11 hours ago, adw said:

The mk11 coil can and does bare the wires and short out just as the leave the crankcase to the carb so take a good look in that area.

No sign of any bare wires, are there any resistance or continuity checks that can be done on the coil while it is out?

 

I have a bit of hedge cutting to do today but will get back on it this evening.

 

Parts are showing as on back order so if I need a new coil it will take a while

 

In the meanwhile I have a Mk1 coil which can go cheap, never fired up, as the owner says it was his mistake so will not ask for a refund and also out of time.

[openspaceman]

 

 

Thanks to a @adw and @spudulike  and all who commented.

 

I went to the L&S site and they do only list the mk1 part in their diagrams so it becomes difficult if you don't have the parts list for your saw (do they still come with the user manual for Huskys?)

 

Very special thanks to the dealer who contacted me pointing out the newest coil is 5827774-04 and supplied one by next day, it is also listed at less than half the price of the earlier ones it supersedes.

 

Saw back up and running ready to return. It was  fiddly separating the old white connector and fitting the new one, I found I had to slip off the flexible carb mount on that side to get enough space for my fingers, other than that a simple job.

 

I am glad it didn't need to be plugged in to diagnostics, what would dealers charge for this and a firmware update if necessary?

[spudulike]

Glad it is all done. I always spend a bit of time if I think the coil has failed as new ones are pretty expensive.

No idea on the CST cost...around 30 mins I would think with the hard part being separating the connector to plug it in to then you need the coil part code to update.

TBH, the info you get off the CST is by far from being definitive for fault finding and have yet to find it useful. The carb settings are usually the most interesting part.

For those that have messed with a cars OBD2 fault finding, these saws are around 20 years behind...no disrespect to Husqvarna....saws just have far few sensors and are infinitely less complex.

[openspaceman]

2 hours ago, spudulike said:

I always spend a bit of time if I think the coil has failed as new ones are pretty expensive.

Yes the one wrongly ordered but suitable for the 550mk1 was about £100, the mk2 older part  582 77 74 01

is a quid cheaper and the current part 582 77 74 04 is listed at just over £50 with VAT so be warned there will be dealers with the more expensive part in stock.