( Part 2 siezures) Oil Ratio and Fuel Poll

[Haywire Haywood]

Never seized one, but did take one from running to not by playing with the carb when I had no clue what I was doing. Rather than suddenly dying, the compression just faded away and it got weaker and weaker over a month or so of intermittent use till one day it stopped mid-cut and wouldn't restart. I'd like to think I'm a little wiser now, but I wouldn't put my check on it.

Ian

 

[rickyrooster]

Ive always run 32:1 mix in all my saws.never had a melt down. Ive gotten saws given to me and bought them but cant say how it happened for sure.

 

[Al Smith]

Any stories on the 32:1 melt downs?

Noticed On the other poll only one person posted using 32;1, and that was me. Maybe the folks that have had 32;1 failures don't use 32:1 any longer, or did not fill in the other poll?

Contrair ,po bear,don't feel like the lone ranger.I've ran stuff at 32 to 1 for years.Never,ever siezed a thing.

I hear about these wizards running 100 to 1 Amsoil,then I read about a siezure.Being a gentleman,I keep my mouth shut but grinning all the while.

Just to bring up a point ,however I have no intentions of starting the oil wars again.Mercy,that was monumental,to say the least.

 

[GASoline71]

...however I have no intentions of starting the oil wars again.Mercy,that was monumental,to say the least.

Sure Al... sure...

Gary

 

[Al Smith]

Good heavens Gary,the oil wars spread accross several forums and nearly started ww#3.Being a respectable member,of course I can't reveal the forums,ya know.

Oh,by the way,hello Ralph,hope you all have a nice weekend coming up.To the rest of the readers,Ralph and I are buddies,we just haven't met yet.

 

[GASoline71]

Good heavens Gary,the oil wars spread accross several forums and nearly started ww#3.Being a respectable member,of course I can't reveal the forums,ya know.

Oh,by the way,hello Ralph,hope you all have a nice weekend coming up.To the rest of the readers,Ralph and I are buddies,we just haven't met yet.

I remember my friend... who could forget it.opcorn:

Good to see ya around here.

Gary

 

[Lakeside53]

Sorry... no "none of the above".

I've never toasted one either... Fixed a few hundred that had been... mostly airleaks, blocked carbs, H set to lean... Can't say it was ever "mix", unless real old mix counts. I have seen a LOT more "hot" run saws since E10, but that's user education to understand they need to be readjusted.


I've also seen saws run at 50;1 with dino oil mix, last thousands of hours.. I run full syn though..

 

[Al Smith]

Well now,the air leak is a horse of a different color.I would have agree that more saws get toasted from air,than oil,or lack of same.

 

[timberwolf]

By the poll, it looks like everyone who uses 32:1 has siezed a saw but me????

What is the story on the 32:1 siezures?

 

[rupedoggy]

Al I have to respectfully disagree with you. I have seen a lot of air leak seizures but by far the most were from using straight gas. With the little bit of oil/mix left in the tank these saws were most likely running 1000/1 ratio. Yes ratio counts.

 

[SawTroll]

By the poll, it looks like everyone who uses 32:1 has siezed a saw but me????

What is the story on the 32:1 siezures?

Maybe they forgot to actually put the mix oil in the gas?:jawdrop:

 

[timberwolf]

LOL, I should have added a poll option for those who ran straight gas and siezed a saw...

Too bad poll options cant be modified.

 

[Lakeside53]

Al I have to respectfully disagree with you. I have seen a lot of air leak seizures but by far the most were from using straight gas. With the little bit of oil/mix left in the tank these saws were most likely running 1000/1 ratio. Yes ratio counts.

O.k.... you win that one

 

[timberwolf]

7 siezures at 32:1, come on, someone step up and explain what happened, Milling? :taped:

Based on the other poll not that many people use 32:1.

 

[blis]

7 siezures at 32:1, come on, someone step up and explain what happened, Milling? :taped:

Based on the other poll not that many people use 32:1.

you can seize saw with any mix, long as its tuned lean enough,..

 

[Lakeside53]

Hmmm... If you start with a tank of straight gas, then add an bunch off oil a "short time" later, maybe you end up with 32:1?:hmm3grin2orange:

 

[timberwolf]

I think there is little debate that manufactures are under the gun from EPA and burning lubricating oil as a side effect of 2 stroke combustion produces higher pollution numbers.

The established 50:1 recommended by manufactures minimizes pollution and keeps the EPA somewhat happy. But even to achieve this manufactures have found the need to spec their own oil and are not content to say any oil will work at 50:1, as they clearly state that if other oil is used it must be mixed at 40:1. Sure it likely sells oil overpriced OEM too.

But does mixing at 50:1 give enough protection, The answer is likely yes based on the number of people using 50:1 (roughly 45% based on the poll here) given that there is no error made in mixing measurements, fuel condition is up to snuff, OEM oil is used and the saw is in good order.

Does mixing at say 40:1 provide any additional protection?

Assuming saws run at a air fuel ratio of about 12:1 like most 2 strokes under reasonable load, There would be one weight unit of fuel and oil per 12 unit weights of air, of this one unit weight of fuel and oil 1 part would be oil to 50 parts gas by volume as it is measured. That works out to an air to oil ratio of roughly 663:1. Having I unit weight of oil per every 663 unit weights of air in good conditions has been demonstrated to work and manufactures stand behind this with a warranty.

Now lets say there is an air leak and 5% of the air coming in is bypassing the carb, there is a primary effect where by the air to oil ratio will go up to 696:1 which then effectively makes the fuel oil ratio equivalent to 53.5:1 instead of 50:1, but there is a second compounding effect, as the velocity in the carb drops so does the quantity fuel pulled in and the air fuel mixture right from the carb (the other 95%) drops and it will end up closer to maybe 12.5, this further hurts the air to oil ratio likely now more in the range of 720:1 or an effective equivalent to mixing fuel and oil close to 60:1.

This goes to say that a 5% air leak would reduce the lubrication at the cylinder walls and bearings by about 10%. Overall the air Fuel ratio has jumped from 12:1 to over 13:1, this increases combustion temperatures significantly as well as upping the RPM. The increase in temperature then reflects more heat down into the engine base and reduces charge density which then again reduces the amount of oil available for lubrication. Likely this heading towards air to oil ratio of over 750:1, equivalent to mixing fuel and oil at 65:1.

Two other bad things happen, as temperature goes up, the piston expands and clearances are diminished and to top that off the little lubricating oil left becomes less efficient as the viscosity and lubricity drop.

Even going with 40:1 fuel to oil would likely not keep the designed quantity of oil present with a 5% air leak, but it might be enough to keep sufficient oil with a smaller air leak of a percentage or two.

 

[RiverRat2]

I had a siezure once!!!!

I was at a friend of mines bachelor party,,,,, I think the siezure was caused and attributed to improper mix ratio ,,,, but i didnt notice @ first cause everytime I would go to the rest room someone was increasing the lube content of my scotch and water when I wasnt looking,,,, rule # one,,,,,, never leave you drink unattended,,,,,,, I woke up the next morning in the back seat of my car in my drive with no keys to be found (they were in tha house) and I didn t smell very good either

Never have siezed a saw yet!!!!!!!

@ least they had enough sense not to let me drive home!!!!!!!!!!

 

[Hozer]

Timberwolf makes good sense!

 

[Haywire Haywood]

Timberwolf makes good sense!

Or at least he talks a good game... :hmm3grin2orange:

Ian