Husqvarna 562xp should we or shouldn't we?

[pleasant]

Well, it's normally me offering advice on repairs, but on this occasion I am after a bit of advice myself.

 

We have had a new customer approach us about servicing and repair of their farm hand held stuff. Initially the call was asking if we would do Stihl...which we do. Upon arrival, the maintenance manager brings into us a couple of Stihl machines, plus two Husqvarna 562xp saws.

 

Now, we used to be a Husky main dealer, but that was near 20 years ago, and pre dates all the electronic gubbins they now fit to their carbs. The two 2020 manufacturerd 562's have this auto tune carb system which my guys aren't familiar with. I took them in because if I didn't it would mean we may lose the rest of the machines....although I did point out we haven't done Husky for sometime. I was assured it was just to service and get going and make them ready for two of his guys to use on a forthcoming CS30/31 training course.

 

We have got to the point of getting them both started, although we haven't thrown a full service at them yet. They both start BUT one has got a very slight hesitation from acceleration on idle....and I mean very slight. A millisecond before it revs up cleanly....but I know it's there.

 

The second one, again starts and revs up and accelerates cleanly but slowly dies on idle.

 

My guys have said there's loads on places like this one and you tube videos advising on how to approach issues with this auto tune system, and highlights some of the issues we have with these two. Particularly the one that dies on idle.

 

My questions is....do we 'have a go' and hope we sort the issues by taking this internet advice, or should I be upfront with the guy and say these two are best left to a Husky dealer?? I don't want to play around with them in the hope the issue is cured permanently, only to find in a couple of weeks time one or both play up during the chainsaw course....and of course the inconvenience and cost of that involved?

 

If it's considered a simple fix and a common one, then I don't mind but it's my name above the door so want to do it properly or not at all.

 

 

 

 

[Mark Bolam]

I would give this a go first, no diagnostic tools required and I don’t think you have anything to lose.

 

https://www.ifixit.com/Wiki/Husqvarna_Chainsaw_Autotune_Reset

[Stubby]

I would try a re set buy cutting the full length of the bar for a few mins on full chat  That should reset the A/T and if that is all the problem is jobs a goodun . You could of course have a slight air leak . So pressure test and vac test like you would any other saw .

[spudulike]

I often found that good old fashion fault finding got most of the Husky AT machines running.

One thing I always checked was that the air filter was clean by looking at it with a magnifying glass and a bright light. People often wash them or just blow the dust off so the open areas get blocked having the same effect as having the choke engaged. The 80 Micron ones do often get blocked.

Other than that, check out the fuel filter, the gauze strainer, the pump diaphragm (flaps may be perforated), muffler spark arrestor, piston through exhaust port etc etc - you know the score....

The only time I reset the machine AT is if I had repaired a fault that the AT may have changed its settings to accommodate such as an air leak or shot piston etc. I never really found an AT reset helped anything as the system just adjusts to the condition of the engine and fuel system. 

Husqvarnas CST does give the current carb H&L settings which can help diagnostics but is no "silver bullet".

It may be worth you having a dialogue with ADW....perhaps via PM, he knows a little about these machines

[adw]

Auto tune is a very reliable system, however it can be its own worst enemy, auto tune will always try to keep the engine at full power, so if the air filter is part blocked it will lean the mixture to compensate, the orange frame air filter is 25 micro and even thought they look clean they can be blocked, and this in turn causes the carb to lean off, depending on the age of the saw there have been many updates, most to improve acceleration and hot restarting, idling is set via auto tune at 2750 rpm, the first thing you lose when there is any cylinder or piston wear is the idle, if these are mark 11 machines a pressure vac test must be done as they are quite prone to the crank seal behind the flywheel leaking.

Hardened metering diaphragms have become an issue due to all the fuel issues we know very well, again depending on the age of the saws a firmware update would be a good idea, also to see the L circuit number, the numbers runs from 5 jet fully open to 150 jet fully closed, this figure can give an idea what may be going on, the fault codes given in cst are all based on these settings, base setting is around 70/80, as Steve said it is still a two stroke engine so can have all the usual two stroke issues, fuel system, engine condition etc.

[pleasant]

Thanks for your suggestions. Based on what you have said, i will initially instruct the guys to proceed down the normal service route and change the service items and check what we would normally do it it were a bog standard saw.

 

Adw....these are both 2020 machines, so is  anything you stated with regards to age in your post more or less relevant? Oh, and they are like new....being used on a farm they arent used full time so havent done a lot of hours 

 

The better one of the two....the one with a very slight hesitation on pick up i ran today and did half a dozen or so cuts in hard seasoned wood on a saw horse that we use for testing.  Cuts like a monster in the cuts and after those test cuts the slight hesitation on acceleration had gone?? I will restart it from cold in the morning and see if still the same

Edited November 7, 2023 by pleasant

[spudulike]

One thought - did you use your own fuel in these machines? I ask as I was working on an HL100 with no idle and the fuel had a lot of water in it. 

Did the usual - leaving it in a clear container and all the water sunk to the bottom!

[pleasant]

First thing we do on an unknown machine is drain out the tank, then if a primer fitted, prime it through back into the tank then tip that out and then refill with our own known mix. Gives us a datum point to work to....plus we can assess the condition and quality of the fuel mix thats come out of it. 

[adw]

2020 would likely make them late mark 1, so I would guess they have the orange frame air filter, so a very good clean , do your machine service, then bury the saw full bar length into a log to reset the carb which may have leaned off to compensate for a blocked filter, they should have most of the updates as they are late machines.

[pleasant]

👍 Keep you posted.