Br 600 Hard starting to no start

[sgkent]

different viscosity oils have different molecule sizes, they also have a composition of additives that are put with them. If those molecules are too large to fully oxidize in the amount of time they need to combine with the oxygen then they are left as engine carbon deposits. The additives help dissolve carbon deposits. A two cycle engine has completely different timing, heat and pressures, than a 4 cycle engine. Most 2 cycles have slots cut in the cylinders where the intake and exhaust flow. A 4-mix engine is bringing the intake in thru an intake valve, and going out thru an exhaust valve. The difference with a standard 4 cycle engine, is that a 4-mix engine brings the fuel and oil in thru the crankcase to lubricate and cool the bearings. Just a guess that they are needle bearings. 2-cycle and 4-mix engines are totally different animals although both are using that oil and fuel in the crankcase and bearings.

We used to work on the timing of 2-cycle racing engines by changing the placement and size of those slots. On a 4-cycle engine you play with the cam duration, overlap, lift, and timing. It may well be that standard 2-cycle oils don't completely burn in a 4-mix engine, as well as they do in a 2-cycle engine, and they may leave deposits on the valves that don't exist in a 2-cycle engine. There are probably other oils out there that will work in a 4-mix other than the Stihl 4-mix oil, which is engineered to leave less carbon and burn more completely that standard 2-cycle oils.

 

[bertsmobile1]

I know how they work & I know how the different oils work & I know how the different lubrication works
But again As far as I have been able to find out there is SFA difference between Stihl 4 mix oil and any other fully synthetic 2- stroke oil
And for all intents & purposes there is not much difference between the semi synthetics & the fully synthetics unless you use the strict definition of a synthetic oil that is made from natural gas
So yes there would be a difference between using standard non synthetic 2-stroke oil , which I have not seen for quite a while down here and a semi- / fully synthetic 2 cycle oil
However I am yet to find any evidence of there being any difference between any other synthetic oil & Stihl synthetic oil other than factory press releases which are ambigious to encourage others to repeat what was inferred & not what was actually said ( very old advertising trick )
I had a scientific education so I am over the moon when some one PROVES my opinions to be wrong because then I can change them to be right ( or the current version of right at the time ) .
I read all of the trash that factories put out to convince me I should be using ( or selling ) very expensive parts with "magic" properties.
Very little of it passes the simpilest of tests .
I currently run engines that are suppose to run 25:1 at 50:1 for at least 100 hrs a year with absolutely no ill effects
According to the makers, if I use their own brand miracle oil which is 4 times the price of the Stens Oil I use at the moment I can run the same engine at 100:1
Will it run at 100:1 on the semi synthetic I use at the moment ? I have no idea but the semi synthetic does not smoke or build up on the plugs or exhausts so I can see little benefit of going to 100:1
Further to that when you get that lean, measuring errors become a problem .

 

[peteco]

Ok why don´t you use the correct oil?

 

[bertsmobile1]

Because I have better things to spend my and my customers money on than buying the same oil in a different bottle with a different colour die in it for 6 times the price
For the same reason I don't buy genuine Kawakasi, Honda, Briggs & Stratton , Kohler or John Deer oil.
Because there is nothing special about any of them apart from the bottle & the price .
The oil I use & supply my customers with works quite fine so it is the RIGHT oil , just not the grossly overpriced Right oil
It is your decision what oil you use & if you have money to burn, or it makes you feel better than the bloke next door then continue to use Stihl's magic elixa
Just don't try to convince people who are confused by all of the advertising BS that anything other than Stihl oil will cause their tools to blow up

 

[Teeton]

Sorry so late getting back yo you all. Thanks gor all your replys.