Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: huntindog on October 23, 2013, 08:02:35 pm

Title: Air fuel mixture
Post by: huntindog on October 23, 2013, 08:02:35 pm
 I was perusing the service manual for my 036 Pro today and this caught my eye:

Fuel mixture:   Regular brand-name gasoline and brand -name two-stroke engine oil 50:1 with STIHL two-stroke engine oil.

25:1 with other brand-name two-stroke, air cooled engine oils. ???

It appears to be saying that other brands of oil ??? need to be mixed at 25:1, while STIHL oil can be mixed at 50:1 ???

I also have noticed that some here are recommending mixtures that are probably close to 25:

This is not what my owners manual states.

Thoughts?
Title: Re: Air fuel mixture
Post by: 660magnum on October 23, 2013, 08:13:01 pm
For the last 40 years I have used 32:1 dino oil in all my gasoline 2 strokes except my outboard motors which were 24:1.

I have not had a single galled cylinder or bad bearing in any of them. I have never used 50:1 anything
Title: Re: Air fuel mixture
Post by: jmester on October 23, 2013, 08:23:48 pm
I agree 50:1 is lite on the oil for my liking, I am running 40:1.
Title: Re: Air fuel mixture
Post by: jmester on October 23, 2013, 08:26:01 pm
That also implies that sthil oil has better standards. Then some cheap brand you pick up at the gas station or Walmart.
Title: Re: Air fuel mixture
Post by: huntindog on October 23, 2013, 08:53:08 pm
The only Stihl oil my saw ever used was what it came with from the dealer.  My manual basically states that any TC rated oil can be used at 50:1... I would have either used the other brand oil at 25:1 or made the effort to get the Stihl oil if the manual had so stated.

As for the better quality, perhaps. Maybe it is just thicker, and thins out less when cut with the gasoline.
Anyone got a bottle of each and want to check it? A low tech viscosity test would tell the truth.

All one needs is a something flat like a paint stirring stick (Even a popsicle stick will do) with a narrow inverted "V" cut out of the bottom of it and a stopwatch.  Make a mark on the stick up where the "V" narrows. Then dip the stick in the oil, and pull it out while starting the clock. Stop it when the oil web in the "V" hits the mark. Then do the same for the other brand of oil.
The thicker oil will be slower to hit the mark.