075 oil to fuel ratio

[NoRush]

I have 2 stihl 075 on my mill and just been reading the instruction manual and it say oil to fuel ratio is 1:40 with stihl oil. The more I read the confused I get. Been running all my saws and stuff on 25:1 for 20 odd years with no problem (stihl and husky). I was thinking that as these were older machines which had run on leaded do they need a bit more oil in the mix. Do I need to make a separate mix for the 075. Will they be ok on the same mix as the rest or will I damage the

Any advise would be helpful

[Stubby]

Most stuff today runs 50 : 1 . That's top quality oil . 25 : I think was when the oil was not so well manufactured . ( 50 parts fuel to 1 part oil )

[NoRush]

My mistake I use one of them litre 2 stroke oils with the measuring chamber on top. Does the 075 need anything extra as it was made in the days of leaded fuel to make it live longer like classic cars need an additives in the fuel

[Garyjp]

The 40:1 ratio is very common in the US as the fuel is typically of lower quality / higher in ethanol and other additives than in europe.

Best be safe and use a quality branded oil and go with the recommended ratios.

 

25:1 is quite high mix ratio and unless it states to use that i would consider revising...Remember you can do just as much damage using too much oil as not enough...

 

Excessive oil can cause the piston ring to become gummed in and allow hot gases to bypass leading to scoring of the piston and ultimately a seizure.

Excessive carbon deposits can also increase the engine temps and if a carbon build up breaks off it can cause a major failure.

 

Check the plug condition if you have been using the same plug for a while..this will be an indicator of the piston and exhaust port state of health.

 

Not too mention the environment and the fog of smoke that you will be enduring as a result of higher oil use.

 

Regards

 

 

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[Stubby]

Not too sure there . I think it was down the soft valve seats in the old engines . No valves in a 2 stroke so don't think so . Bore my not be so hard wearing ( nicosil etc ) . Best check with spud , he will know .

[wisecobandit]

I tend to mix mine around 40.1 in the 051's and 075's and never had a problem.

I share the same view as stubby that there are no valves to burn out and oil is much better quality than when these saws where made.

Just keep an eye on the colour of the sparkplug from time to time. The nice thing also is theres no rubber inlet manifold to split and leak etc (tho it pays to change your impulse line if your not sure when it was last done)

[muttley9050]

I run my 076 and 051s on 25:1 with no lead replacement. 076 been running like that for 15 years. No problems but is is rarely used

[spudulike]

Back in the day 25:1 was common as the oil was of much poorer quality than today. Modern oils are far better quality now and 50:1 is recommended by the oil manufacturers and is the correct ratio.

 

25:1 will cause carbon deposits and smoke excessivly so stick to 50:1 or as the oil manufacturer states.

 

All the tuned saws I run do so on a 50:1 mix and they rev up to 15,000rpm, your 076 will plod at around 9,000 full tilt so will run fine on that ratio.

[agg221]

Mix ratios are all about the quality of the oil, rather than the saw.

 

If you've got top quality oil recommending 50:1 then you mix at 50:1. Lower grade oil stating 25:1, that's what you need.

 

For info, I have a 1948 Teles 2-man saw, together with an Allen Scythe courtesy of Geoff, which gets some serious use a couple of times a year when it mows the paddock with thistles in it taller than me. Both state on the fuel tank cap that they should use Castrol XL at 16:1 but they really like Aspen at 50:1, as do my lungs compared with the smoke they used to kick out

 

Alec

[Brownlie1985]

Running a 009 with 25:1 which my dad bought in 1985. Used and abused for 28 years... And the saw has seen a great deal of use too.

 

 

 

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