Argument is how we learn; it prods us to collect evidence for our positions. If there is concrete evidence one way or another I'll go that way. I'm still unclear why Husqvarna recommends 50:1 to US users and other ratios to non-US users. Having said that, there is no argument that 33:1 or 40:1 is certainly something to try.
What's the justification for not using 50:1 for milling?
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A burned up saw is rather concrete evidence. Making me wonder if this is a troll.
Not at all. There are multiple possible causes for burning up a saw. I'm trying to disentangle these factors and understand which are important or unimportant. For example, there's no debate that running low octane fuel is no good. Also, tuning the carb rich is clearly important. Muffler mods do seem to help. I'm unclear, however, why Husqvarna recommends 50:1 for the US and other ratios elsewhere. Why might this be? It might be due to different fuel quality in various countries, in which case it would be an important factor in deciding whether or not to go the 40:1 route. It also might be due to EPA reasons, in which case we should go 40:1. And so on.
To put it another way, you say "a burned up saw is rather concrete evidence". But what exactly is it evidence of? There isn't usually just one factor involved.
To put it yet another way, I'm not "arguing" for just the sake of it, but in order to learn. One doesn't learn by simply taking someone else's word on things blindly.
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Because they want to keep the EPA happy. Recommendations are often made to make the EPA happy rather than to take good care of saws.
That was kinda my suspicion.
Me too. A good carb tune keeps my plug and muffler looking fine.
EggZaklee
very very few people learn anything from arguing, You have to take the advise given, and try it, otherwise you will never know for sure.
But considering YOU are the only one sticking to the 50:1 argument, and a whole lot of other folks have gone before you and had good results with 30 or 32 to 1...
Maybe you should go try it.
You misunderstand. I'm not sticking to the 50:1 argument, as you'll see if you read what I wrote. I think I said explicitly that I'll give it a shot, and that the thing I was unclear about was why it is that Husqvarna says 50:1 for the US and other ratios for non-US. A commenter pointed out that this is probably EPA shenanigans, and I agreed. My opinions have definitely changed during this thread, and that's great! I think the key for me was the fact that Husqvarna does recommend 33:1 in >75cc chainsaws. Problem is, I was following my (USA) manual where they say 50:1.
So, new plan:
- Use 33:1
- Retune carb to around 11K after changing mix (I wish I could do it by ear but I'm not confident of my abilities in that regard)
- Use IR thermometer to monitor in long cuts
- Check tach reading every time weather changes drastically - things get leaner in the winter
Your saw didn’t need the extra oil to keep from scoring, it needed extra fuel mixed in with the air to cool the piston. Had your rod bearings or case bearings burned up, that would indicate the need for more oil, but it doesn’t usually show up in just a few hours of run time.
I would run a good oil at 32:1 and remove the carburetor limiter so you can adjust it just on the edge of 4 stroking while in the cut
I would run a good oil at 32:1 and remove the carburetor limiter so you can adjust it just on the edge of 4 stroking while in the cut
Excellent info, thanks! My next project is to really learn what 4-stroking sounds like. I have videos and tutorials lined up, just have to experiment.
Unless you are a politician…
It's in all the older manuals, I believe they took it out in the more recent revisions after looking at the operator manuals I have for my 359, 390xp and 394xp. All 3 manuals reference a 33 to 1 ratio if not using husqy oil, or using an fb or iso egb oil. The 390xp and 394xp manual both have the statement if used for heavy duty purpose to mix at 33 to 1. I looked up a 390xp and 395xp manual from 2020 and 2023 revision and neither have this reference. I find that kinda odd as it's one of the few things changed when they completely dropped the 385xp and 394xp out of the current manuals.
At any rate it just simply not enough oil, and years of favoring a higher ratio even by the manufacturer should not be ignored.
Yup, my 395xp manual from recently (I bought the saw in 2021) has no reference to 33:1. Very odd. Perhaps something changed with EPA standards around then. I agree that years of favoring a higher ratio shouldn't be ignored.
Dennisthemenace
ArboristSite Operative
What's the justification for not using 50/1 when milling?
1) Your story
2) Not everyone is particularly good at tuning so more oil will add a small margin for error
3) Some blokes leave the limiters in (see points 1& 2 above)
1) Your story
2) Not everyone is particularly good at tuning so more oil will add a small margin for error
3) Some blokes leave the limiters in (see points 1& 2 above)
I've seen a discussion previously where someone had emailed Husqvarna regarding the inconsistency in recommendations. The response was that some manuals varied in different geographical locations due to local laws &/or regulations.
The "more oil under harsh conditions" should stand regardless if you care about the longevity of your saw.
Milling puts about the most significant load a saw could expect to see on it... & it does this for an extended period of time. This creates a significant amount of heat for the saw to dissapate & everything you can do to help the saw disperse this heat will help the piston not melt.
A muffler mod allows the hot exhaust to escape faster.
More oil helps with lubrication & aids compression (this improves efficiency but higher compression can create a tad more heat)
Fuel plays a massive role in cooling a 2 stroke motor, & a lean burn is also hotter... so there is significant cooling introduced with additional fuel.
I generally run my saws on a good FD rated Synthetic at 40:1 & mill with a Husky 390 at 33:1 & tuned around 500RPM below max. I've done more 20' cuts at ~30" than I care to count, never felt the need to stop mid cut but always allow the saw a minute of idle time at the end of a long cut.
The "more oil under harsh conditions" should stand regardless if you care about the longevity of your saw.
Milling puts about the most significant load a saw could expect to see on it... & it does this for an extended period of time. This creates a significant amount of heat for the saw to dissapate & everything you can do to help the saw disperse this heat will help the piston not melt.
A muffler mod allows the hot exhaust to escape faster.
More oil helps with lubrication & aids compression (this improves efficiency but higher compression can create a tad more heat)
Fuel plays a massive role in cooling a 2 stroke motor, & a lean burn is also hotter... so there is significant cooling introduced with additional fuel.
I generally run my saws on a good FD rated Synthetic at 40:1 & mill with a Husky 390 at 33:1 & tuned around 500RPM below max. I've done more 20' cuts at ~30" than I care to count, never felt the need to stop mid cut but always allow the saw a minute of idle time at the end of a long cut.
StihlPotlicker
ArboristSite Operative
I run Stihls. but I have bought a Egan straight shot, and I have removed the baffle and opened the exhaust hole. not sure on a husky muffler.
StihlPotlicker
ArboristSite Operative
EPA BS. blame California, that is why when Europe, Germany or Sweden releases a new saw, the US is always 1.5-2 yrs behind on getting them, because they have to go through rigorous checks. I have a buddy out west that bought a Eruopean saw, and it runs better than his saw that he bought in the USA.
Good morning all.
I have read the entire thread. HarleyT made one comment about the "Oil thread" (funny) and I'm amazed that nobody has mentioned the fact that resistance causes HEAT. All are talking about oil mix, etc. Nobody has asked the OP if his chain is sharp and in top notch condition. Just curious.
I run a Wood Mizer LT40HD. If I hit just one little fence staple, piece of fence, etc., it's time for a new blade. Ya never know what you will find in a log. JMHO OT
I have read the entire thread. HarleyT made one comment about the "Oil thread" (funny) and I'm amazed that nobody has mentioned the fact that resistance causes HEAT. All are talking about oil mix, etc. Nobody has asked the OP if his chain is sharp and in top notch condition. Just curious.
I run a Wood Mizer LT40HD. If I hit just one little fence staple, piece of fence, etc., it's time for a new blade. Ya never know what you will find in a log. JMHO OT
