Jim Timber
Veteran Member
Bottom ends burn up if you run 50:1 on a ported saw - it's too little lube. I've switched to the heavier ratio in all my saws. More oil never scored a cylinder or stuck a ring. 
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motownbrowne
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Just because the manual says 50:1 doesn't mean that's what people run. I know lots of guys run 32:1. I generally run 40:1. A bottle of oil that makes 2.5 gallons of mix gas at 50:1 makes 2 gallons of 40:1.
Creamer
Elite Member
For what reason? If the engine was designed at 50:1 you are changing characteristics by putting something else in it and taking it away from its design optimum.
motownbrowne
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The reason, as Jim stated, is for extra lubrication. You're right you change the characteristics. It has the effect of leaning out the mixture that gets burned. This is easy to compensate for since there are adjustments on most saws to dial in the fuel/air mixture.
The guys on the chainsaw forums think they know more than the manufacturers. They think they are extending the life of their saw. Most guys on the saw forums run 32:1.
4570Man
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I might consider 40:1, but 32:1 is ridiculous. I'm not a fan of a trail of blue smoke coming out of my equipment. I suppose I should add extra oil to modern diesel fuel too.
Jim Timber
Veteran Member
You might want to do that instead of replacing injectors. Just say'n...
In order to run 32:1, you need to jailbreak the EPA limiting caps put on every new saws carb adjustment screws. When delivered from the factory, they're set so lean they'll make the emissions lifespan (indicated in hours, found on the saw's package: some are 125 for consumer saws and pro saws are usually over 300) but not much life left after that. Or you can remove the limiters and richen it up and enjoy minimal wear for the decades you're used to getting out of saws going back to the '70's.
Oil technology has improved in the last 5-6 years, but fuel quality continues to go to crap. I run 91 octane non-ethanol because I can't buy 87 octane non-oxy in my area thanks to the stupid ethanol lobby in MN. Go to South Dakota and they have 87 non-oxy and it's even 10 cents cheaper than the adulterated 87 octane garbage in the pump next to it. Go figure! Running your saw too lean will burn it up. Running more oil than 50:1 actually reduces the octane rating, so you need to fatten up the mix to keep it from pinging. When I pull a jug, there's a nice film on everything in the case since switching to the 32:1/91 non-oxy. When I was running 50:1 or even 40:1 and 87 ethanol crap, there was never any signs of oil in the case. It felt dry!
So, do whatever you want with your saws. Open one up sometime after you've been running it and see what's in the case. Main bearings need oil.
My saws don't smoke, and I use a tach to set them.
s219
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I think a common mistake when mixing oil is to think the ratio is based on the equipment, but in reality it's based on the oil. A modern synthetic at 50:1 is lubricating as good or better than older dino at 32:1. That's why we can run older equipment with a 50:1 synthetic mix and it ain't going to skip a beat or burn up, even though when the owner's manual was written, 32:1 oil was the state of the art. With 50:1 synthetic, it's getting as good or better lubrication than it did in the old days at 32:1.
If you're taking a 50:1 spec oil and mixing it to 40:1 or 32:1, it's just a waste. If someone really wants to run 40:1 or 32:1, look for a low tech dino oil that calls to be mixed to those ratios. I don't see the point, of course.
If you're taking a 50:1 spec oil and mixing it to 40:1 or 32:1, it's just a waste. If someone really wants to run 40:1 or 32:1, look for a low tech dino oil that calls to be mixed to those ratios. I don't see the point, of course.
Jim Timber
Veteran Member
Look at the Euro spec on a Husky 80cc+ saw and you'll find it's not told to be using 50:1 like they do here. 32:1 is being safe. Safe is cheaper than a new slug and jug.
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If one is a logger who puts many hours on a saw on a daily basis, I can see having the latest-and-greatest. But
even THOSE guys could buy an older saw, and fix it indefinitely. All the wear items for an MS440, MS660, 3120,
or 372XP, etc. will be available for decades to come, and full refurbishment costs substantially less than
a new saw at that level.
If FI means more "drivability", as it does with autos, I am for it. It would run cleaner, too, but there is a definite
maintenance price to be paid.