Repeated scored pistons on Stihls - time to switch to Aspen?!

[GardenKit]

Firstly, neither Stihl or Huskie will invalidate warranty if Aspen is used. Nor will any other manufacturer. I have spoken directly to both Stihl and Huskie on this matter. In fact I even had one seized engine passed under warranty purely because, as it had been used solely on Aspen there was no question of incorrect fuel.

 

The dealers who make these claims of invalidated warranty really need to get themselves educated, firstly on their warranty terms and secondly on identifying the real cause of failures. They also need to learn about Aspen.

 

The fact is, that Alkylate fuels are much purer than pump petrol, so much less likely to cause any engine damage than the rubbish petrol that is used generally.

 

The Scandinavian countries and the Netherlands use alkylate fuels as the norm in this type of kit, do you think all their saws are invalidated from warranty?

 

Secondly, what happens when petrol ages?

Many, many things happen due to chemical reactions. These are just some.

• The oil is intially 'bonded' with fuel, or 'disolved'. After a while the oil seperates from the fuel so that the oil particles are suspended, rather than disolved. Sure, they are still there, but pass through the engine in the form of smoke rather than being totally used during the lubrication process. The result can be a seize due to lube deficit if the machine is worked particularly hard. This separated oil does not rebond with the fuel when shaken.
  

• The fuel loses its octane rating as well as its calorific value as it ages. This effectively means there is less usable fuel in relation to the amount of air in the mix, so the engine runs lean. This causes a much hotter run temperature which results in a 'lean sieze' when worked hard.
  

• Remember, both of the above are happening at the same time, which makes matters far worse.
   
  
• Because of the ethanol content, the petrol is soaking up water from the atmosphere. After awhile the ethanol/water mix undergoes a reaction called 'phase seperation' where the mix changes into a clear jelly like material, clogging the carb.
   
  
• Other 'varnishes' are also formed in the fuel, coating the insides of the carb
   
  
• The above changes are all happening together, and only take months, rather than years to occur.
  

 

Of course, we know that not all machines fail after using stale fuel, but many do.

Some of you have been lucky and believe there is no problem, but you are wrong. Just lucky.

[Mountain man]

All good points, however I have saws and hedgecutters over 15 years old.

I've only ever used aspen once, on my 088.

All the others have always run on petrol station petrol and husky/stihl 2 stroke.

 

Aspen/motomix for me = Emperors new clothes.

[GardenKit]

All good points, however I have saws and hedgecutters over 15 years old.

I've only ever used aspen once, on my 088.

All the others have always run on petrol station petrol and husky/stihl 2 stroke.

 

Aspen/motomix for me = Emperors new clothes.

 

Then you probably have a good method of fuel managemant.

 

Or you do not work your kit too hard.

 

Or you are just lucky.

 

Or all of the above.

 

There is no doubt that 80% of small engine repairs are due to fuel problems.

[Eddie@aspen]

Over the past four years we've had the piston seized / scored three times on our 660 and once on a 260. Prior to this it never happened. We had our previous 066 for 15 years with no issues.

 

Has anyone else been having these problems?

 

We've been using the higher grade green Stihl mix for the last couple of years. I have been paranoid about my fuel mixing and the 660 piston scored again last week.

 

I decant from the 5L mix container into a 1L one with the squeeze measurer for 5L of fuel. I always make sure slightly above the line. I am the only person who mixes the fuel. I only mix into 5L containers - so no possibility of getting mix wrong. Since the last time the piston went I only buy super unleaded fuel from a branded oil company garage (usually BP).

 

I have been thinking of switching to premixed Aspen to rule out any issues with fuel. At Lister Wilder in Cirencester today we were informed that Stihl and Husqvarna won't honour warranties on saws if they find Aspen has been used - they require you to use their mix. Can anybody tell me if this is correct? I thought Aspen was regarded as the highest grade fuel you can buy?

 

If Aspen no good then we'll have to buy another big saw and always carry two on bigger jobs. This is a total pain in the arse!!

 

Any thoughts / suggestions appreciated...

Hi all,

 

I have a letter from Stihl saying Aspen does not affect warranty.

Husqvarna run every 2stroke on aspen in the factory and the UK workshops buy Aspen from me. Aspen is even listed in the Husqvarna catalogue.

 

I will call Lister Wilder in Cirencester on Monday and get this sorted.

 

If you have any warranty problems because Aspen has been use contact me on 07568 108953 or email [email protected] I will sort it all out for you.

 

Please keep me informed if our dealers are giving out incorrect information.

 

If you have any Aspen questions or concerns please contact me direct.

 

All the best

 

Eddie

[Eddie@aspen]

How quick should you use mixed fuel? I keep an emergency 5l mix in the truck but we rarely need to use. Having read the above posts I am thinking I should start an organised rotation? Thanks

Nick

Hi,

 

Fuel can breakdown in as little as 4 weeks so try not to keep it longer than that.

[Rob D]

I've scored I think perhaps x2 pistons in my time - at the time could not understand why - now I know it was user error.

 

 

First was an MS170 - thought I'd have a go at carving - hollowed out some old rings to make bird boxes - was using near full throttle (instead of half/feathering) - over heated and this scored piston....

 

 

Second was an MS880 - continuous milling in hot weather - not resting the saw down the cut - dull chain - switching off without allowing saw to cool off for a min or two...

 

 

It's not always fuel but how you treat your gear.

 

Don't run out of fuel (I have found always running the saw until it starts to miss and rev begins to effect how it will start and how it idles) and if doing long prolonged cuts allow a min to idle to cool off.

[GardenKit]

 

 

It's not always fuel but how you treat your gear.

 

.

 

True, you can treat your gear really well, but stale fuel will kill it quicker than fresh fuel when the going gets tough.

 

This is a fact that is beyond question.

[Mountain man]

Then you probably have a good method of fuel managemant.

 

Or you do not work your kit too hard.

 

Or you are just lucky.

 

Or all of the above.

 

There is no doubt that 80% of small engine repairs are due to fuel problems.

 

Probably yes, some of the above, one thing I always do with tools that are going away for an indeterminate period ie big saws or seasonal stuff like hedgecutters is run them completely out of fuel. It seems to work for me.

Clients often bring out their saws to me and ask why it won't start, it's always been in the shed for months with a tank of mix.

Believe it or not I recommend that they use aspen or similar for their annual log cutting day.

For me it would be too pricey day in day out.

Ps previous post, bit harsh, apologies.

Edited November 22, 2014 by Mountain man

[agg221]

I've had similar issues in the past.

 

Have you had the saws pressure/vac tested? I have this done (by Spud) religiously. My 066 has just survived with the plug white due to being very cautious - turned out to be a blocked filter in the carb which hadn't been apart in about 20yrs so reasonable.

 

Mine is de-tuned (again by Spud) as per his comments. I really don't notice under-performance. If it was a race saw I would suffer but I mainly use it for long, hard cuts and would rather it had some leeway.

 

I once lost an 064 and 066 pot and piston in the same day thanks to a dodgy batch of fuel (not supermarket and freshly mixed) so I now use Aspen as it never gives me problems and it doesn't get stale so can stay in the tanks without thinking about when I last used a saw. It also doesn't age the rubber components. No problems since I switched over, and rather more pleasant exhaust fumes too.

 

Alec

[GardenKit]

Mountain man

No, it was not harsh at all.

Just good contribution to the debate.