What's the justification for not using 50:1 for milling?

[anynameyouwish]

So I just recently overheated my saw while milling, and though it can be repaired (and it goes into the shop tomorrow first thing), I would like to make sure it doesn't happen again. Clearly I need to be more careful about letting the saw idle to cool down after a few minutes of hard cutting, and take off the damn carb limiters so I can set it to a slightly richer mix than I've been using. But one thing I still don't get is the justification for using 40:1 or 32:1 gas/oil. My understanding is that older saws did need this ratio, but modern saws don't. Indeed, it just adds more smoke into your environment and fouls up the carbs with excess carbon, and so on.

Is there any evidence that milling in particular requires more oil than 50:1? In particular, is there any reason to think that it will keep the saw cooler?

 

[northmanlogging]

more oil=less friction=less heat
the smoke isn't much different at 40-1 over 50-1
play with fuel grades too, I'm not positive cause I haven't played much with it, but have noticed some rather noticeable differences between 87-92 octane.

 

[anynameyouwish]

more oil=less friction=less heat
the smoke isn't much different at 40-1 over 50-1
play with fuel grades too, I'm not positive cause I haven't played much with it, but have noticed some rather noticeable differences between 87-92 octane.

More oil of what kind, though? What I've read is that modern synthetic oils (which I use exclusively) lubricate better so you don't really need the extra oil. 50:1 synthetic works just as well if not better than 40:1 old school oil.

I'm with you on fuel grades, though. I use the highest octane non-ethanol gas I can find, which around me (Vermont) is 91.

 

[northmanlogging]

More oil of what kind, though? What I've read is that modern synthetic oils (which I use exclusively) lubricate better so you don't really need the extra oil. 50:1 synthetic works just as well if not better than 40:1 old school oil.

I'm with you on fuel grades, though. I use the highest octane non-ethanol gas I can find, which around me (Vermont) is 91.

any oil, if the "synthetics" work better, then more is going to be even better. 2 strokes don't use oil in a traditional sense, the oil is atomized, and just the minimal amount necessary to keep things lubed under "normal" circumstances is calculated, largely for emissions purposes, hence why older saws ran 32:1...

Adding even just a little bit more means the bearings and more importantly the cylinder and rings have a thicker film of oil, as it is that wee little film is all that a 2 stroke has for lube, add a bunch of extra heat from say milling, then that little film goes away quick fast in a hurry.

The down side is you run the risk of fouling more plugs, but its not like a huge risk

 

[The Stig]

I run all 2strokes synthetic 32:1

 

[Lightning Performance]

So I just recently overheated my saw while milling, and though it can be repaired (and it goes into the shop tomorrow first thing), I would like to make sure it doesn't happen again. Clearly I need to be more careful about letting the saw idle to cool down after a few minutes of hard cutting, and take off the damn carb limiters so I can set it to a slightly richer mix than I've been using. But one thing I still don't get is the justification for using 40:1 or 32:1 gas/oil. My understanding is that older saws did need this ratio, but modern saws don't. Indeed, it just adds more smoke into your environment and fouls up the carbs with excess carbon, and so on.

Is there any evidence that milling in particular requires more oil than 50:1? In particular, is there any reason to think that it will keep the saw cooler?

What saw are you using to mill with?

 

[anynameyouwish]

What saw are you using to mill with?

395xp

 

[HarleyT]

 

[The Stig]

View attachment 1116829

The never ending oil thread

 

[Lightning Performance]

395xp

You can tune that pretty rich and it will clear up under a load. Older saws have flood limiters built in and many people forget that. It will always run rich at high RPMs. 395 never had that feature. Find the problem before you fix it is the best way. Hope you have a good diagnostic person. It's not always your fault. Buy a tachometer if you need to. Check it red hot when cutting just lift.

 

[Lightning Performance]

I run all 2strokes synthetic 32:1

View attachment 1116825

What does cookie moster run
35-1?

 

[Lightning Performance]

View attachment 1116829

Too much?
Sorry your saw burned up OP

 

[anynameyouwish]

You can tune that pretty rich and it will clear up under a load. Older saws have flood limiters built in and many people forget that. It will always run rich at high RPMs. 395 never had that feature. Find the problem before you fix it is the best way. Hope you have a good diagnostic person. It's not always your fault. Buy a tachometer if you need to. Check it red hot when cutting just lift.

Could you elaborate on "Check it red hot when cutting just lift"? I take it you mean warm the crap out of it and then check RPMs WOT without load and make sure they're on the rich side (say 11.5K)?

Just ordered a good tach as well as an IR thermometer and I mean to get a bit obsessive about checking temps and RPMs from now on. Pain in the **s but better than burning it up again!

What I think burned it was that after almost the full 23-ft cut I ran out of fuel, and may have been slower to respond than I should have. If I continued cutting for even a few seconds after that long cut (with rest breaks of 20 seconds every 6 ft) that might have done it. Don't know for sure, but I'll ask the repair shop to diagnose and let's see.

 

[82F100SWB]

Husky themselves doesn't reccomend 50:1 for your application

More oil and running on the rich side is the way to go for milling.

 

[ballisticdoughnut]

Seems you have some kind of mental block when it comes to running more mix oil. What’s the harm in giving it a try? More oil means more protection period, especially in a hard use application like milling. If you keep doing things the way you’ve been doing them, your gonna continue to get the same results.

 

[jellyroll]

32:1 and tune it to 4 stroke out of the cut but cleans up in the wood. You won't get excess carbon running more oil that is wrong with modern oils if anything it will be cleaner more oil = more detergent use a quality FD rated oil like red armor or Husqvarna XP+

 

[anynameyouwish]

Husky themselves doesn't reccomend 50:1 for your application
View attachment 1116846
More oil and running on the rich side is the way to go for milling.

That's interesting, thanks!

 

[anynameyouwish]

Seems you have some kind of mental block when it comes to running more mix oil. What’s the harm in giving it a try? More oil means more protection period, especially in a hard use application like milling. If you keep doing things the way you’ve been doing them, your gonna continue to get the same results.

Well, the harm would be more fouled spark plugs. If there is an advantage which overrides that disadvantage then I'm all for it. I was just wondering if there is any actual evidence that links more oil to better operating temps. The image posted by @82F100SWB is very persuasive in that regard - after all, the Husqvarna engineers know what they're doing. I'm going to give it a try.

 

[bwalker]

Well, the harm would be more fouled spark plugs. If there is an advantage which overrides that disadvantage then I'm all for it. I was just wondering if there is any actual evidence that links more oil to better operating temps. The image posted by @82F100SWB is very persuasive in that regard - after all, the Husqvarna engineers know what they're doing. I'm going to give it a try.

More oil doesn't foul plugs. Overly rich carb tuning fouls plogs. You can run 20:1 and not foul a plug if your tuned right.
Plug fouling is largely a thing of the past with modern ignition and oils.

 

[OM617YOTA]

I've run 16:1 on accident with MX2T doing firewooding, no fouled plug.