Homelite and mcculloch chainsaw fuel mixture

Before the late '60s it was 16:1 for Homelite's oil, 10:1 for other brands.
From then until the '80s, most said 32:1 for Homelite's and 16:1 for others. I haven't paid attention to Homelites designed after that time, but I believe the the current ones take 50:1.

I run my Stihl trimmer at 40:1 with the GS oil and it runs like a top, never smokes, and the fuel doesn't go bad as quickly as with other oils.

• Wheatfarm.com

I have seen synthetics that are 100:1 oils, and I wouldn't be surprised if some have gone beyond that. But as I indicated in my original post, in spite of the advantages provided by synthetic and super lean conventional 2-cycle oils, they do shorten engine life. I say that based on both personal experience, and unpublished tests done by a major synthetic oil manufacturer...Al English

Homelite is 32:1 .

I personally mix 32:1 for everything I have . I have never had any trouble and don't have 2 or 3 gas cans .

Ford Man

The owner's manual for the Mac ProMac610 lists 40:1 if you use McCulloch's 40:1 2-cycle oil or 20:1 for any SAE 40 2-cycle oil.

Rod

I have answered this question several times in the past, so I hope no one minds seeing more or less the same post again.

What I'm going to tell you applies to all "pre-mix"(non-oil injection) two cycle engines, EXCEPT ones which have one or more plain bearings(bushings) rather than all ball, roller, or needle bearings. Unless you have a VERY old saw, it will not have any plain bearings.

The oil, and not the engine, determines the mixing ratio. The penalty for using a "richer"(more oil) oil mix than the oil manufacturer specifies is slightly less power, shorter plug life, and faster accumulation or carbon deposits. The penalty for using a "leaner"(less oil) oil mixture than the oil manufacturer recommends is shorter engine life. Unless maximum power is more important than engine life do not use synthetic oil in a two-cycle engine. And for the same reasons, also avoid the super lean mixture(more than round 50:1) type oils.

If you have an old saw that has one or more plain bearings, use a conventional/traditional 16:1 2-cycle oil mixed at that ratio...Al English

I personally don't agree with that idea. New oils at the old ratios in old saws will only foul the plugs as much as the original mix did. I run all my old saws at the old ratios specified for the manufacturer's brand of oil. No problems there, and I have a 30 year old high-compression saw that has never needed a rebuild.

later,dave

I suspect you already know this, but maybe someone else would find it interesting.

One of the problems with pre-mix 2-cycle engines is that when the engine is running at high load and/or RPM, and then the throttle is closed, not enough fuel/oil is going through the engine to lubricate it. In a saw that's not a big problem, but in a bike or snowmobile the engine doesn't immediately return to idle when the throttle is closed. To help compensate, a richer than ideal oil mix is used. That is one cause of the plug fouling you mentioned.

Snowmobile plugs must also cope with an unusually wide range of engine loads, engine temperatures, and inlet air temperature extremes. All two-cycle engines demand a lot of their spark plugs, and maybe nothing asks more of its spark plugs than a snowmobile. Unlike today's gold, platinum, and iridium alloy plugs, the older plugs simply lacked the thermal operating range demanded by a snowmobile. Oil injection, better plugs, better ignition, improved engine design, and water cooling, have all helped snowmobile spark plug dependability...Al English

I have a Mac Pro 610 that I bought in 1980 and use 20/1 to 25/1. I tried some of the 50/1 oil but my saw didn't run that well so I went back to 25/1 mix. Problem solved. I'ver never did anything to the saw other than put in a couple new spark plugs over the years. Bars & chains is a different story!

Have you ever bought parts for yours? If so where?
I need a start cord spool as mine has cracked but still works.

T_Bone

Good luck in finding any parts for that 610. A Mac graveyard maybe? If you are fortunate to find any NOS parts, they could run you more than the saw is worth! Last time I got any parts for a Mac I had pay a small fortune...for a muffler as I recall. Time to move up to a Stihl or Husky? Just joking :o).

Rod

Mac has a muffler? LMAO

Well after 22yrs I've gotten my moneys worth so if it takes a dump, then I'll prolly go Stihl and hope for another 22yrs. I cut about 5 cords a year so not heavy used.

I thought about making one out of aluminum but who knows.

T_Bone