So I just got a new Husky 390xp and plan to run it for the first time this afternoon. I have purchased new saws before and just ran em. However, I have heard more about breaking a saw in. My nephew, who knows more about saws than I do, says I should run a richer mixture (40-1) for maybe the first 4-5 tanks. I have not had any issues in the past but am curious to hear from people who know more than me what they think about this.
I run 40 : 1 all the time and have had zero problems. The main reason is because of running the CSM , it is tough on equipment. I have been running non ethanol fuel and Mobil 1 two stroke oil ( on my last quart and this is no longer available here in the US ) mix for years now in all my two stroke stuff , chainsaws , trimmers and blowers all get this. Zero problems , never a fouled plug or any bad looking plug from the extra oil. The 40:1 will actually make your saw run slightly leaner , yes I did say leaner and not richer. The extra oil in the mix takes the place of some of the fuel in the mixture so technically the saw gets less fuel but more oil. Not sure on how others feel about 40:1 but me personally would say yes to that.
I’d run 32:1 in a 390 personally. The crank and bearings aren’t weak, but they’re the weakest link on the saw. The quality of the oil used and tune means just as much as the ratio though, in my opinion
I run 40/1 in everything. For a new saw, or a new top-end rebuild, I tune the carb a little fat for a tank or three, then lean it out to just 4 stroke (when fully hot) unloaded, checked while cutting. The 40/1, or any ratio w/ more oil than 50/1, gives those bottom end bearings more lube and that is a good thing! If you're set on 50 though, tune the H on the carb ccw to richen up the a/f.
I run 32:1 in mine, good synthetic Dolmar brand oil. Mine get run like the rented mule when work needs to get done. Haven't blown one up yet due to a fuel or bearing issue.
I run non-e in all machines, and went to 40:1 years ago for piece of mind. On older saws I would rather see a little smoke and just keep the plug clean. Only burned up one saw, and that was from straight gassing it....BTW I got non-e today at $2.65/gallon
I run 32:1 H1-R in all my 2 cycle stuff. Like Huskihl mentioned, it's not a bad thing to give the big end a bit more oil. Also aides in ring seal too I'm guessing.
Always ran 40 to 1 until my 660 melt down, could have been worn seals, now 32 to 1 all equipment. Seem to run fine with little to no smoke and no plug problems.
What Kevin said ! I run a sort of compromise mix in mine at about 36-1 . That keeps the Auto tune/ M-tronic saws happy ,as well as the 390’s bearings . It’ll run a 32” bar well enough . But , it seems happier ,and best suited for a 28” bar . At least that’s my experience with the 390 .
I’ve always just run 50:1 with no issues but if so many are running it richer, I may start too. So let me make sure I have the math right. If I have a mix for 2.5 gallons and I only mix it with 2 gallons of gas, that will now be 40:1 correct?