converting 40::1 to 50:1

Status
Not open for further replies.
C

cpjr

Joined
Dec 22, 2009
Messages
3
Location
tx
I was able to find some trufuel 40:1 fuel on a clearance sale. My Echo equipment calls for 50:1.

I just wanted to verify my calculations were correct.

40:1 trufuel would have 128 oz fuel and 3.2 oz of oil.

32 oz of this mix would be 31.2 oz fuel and .8 oz of oil (40:1)

To make this mix 50:1 I would need to add 8.8 oz of 4 cycle fuel, which would give me 40oz of fuel, with .8 oz of oil.

Does my math look correct ? My Echo deal swears up and down that the 40:1 fuel will damage the echo trimmer ? I don't know that I agree, but he is the one that would be doing any warranty service I may need for the next 5 years.

thanks
 
Correct, that is why I am asking if adding 8.8 oz of fuel would make a 40:1 into a 50:1
 
Last edited:
32oz can/41 parts is .780 oz/part. You currently have .78 oz oil/qt (3.12/gal) to be precise and 31.22 oz of fuel.
If fuel is equal to 50 times the oil (.78 oz) then you need a total of 39 oz fuel so add 7.78 oz more fuel.
 
Originally Posted By: WobblyElvis
I have run 2 stroke engines anywhere from 20:1 to 80:1. Never made any difference to me. I wouldn't bother changing anything.


Lucky you. I had a friend lock up his Vespa engine on the highway while the correct mix just by using cheap oil.
 
I'd just use the tru-fuel as is, and tell the dealer whatever he wants to hear if you have a warranty issue. Say its tru-fuel 50:1 if needed.
 
You're playing with such small quantities of additional fuel needed I'd be afraid of going greater than 50:1. People on this site run their 50:1 OPE's with anything from 32:1 to 50:1 with synthetic blends. Some full synthetic 2 cycle oils can go to as high as 100:1. I'd run the 40:1 with no problem. Mixing your own oil and fuel is not precise in reality, yet engines don't destruct for minor variances in the mixture ratio.

Whimsey
 
Originally Posted By: Miller88
Have a weedwhacker that uses 40:1 and a snowblower that uses 50:1 - they both get 40:1. Seems to work fine.

That's what I do too. My cultivator, chainsaw, trimmer, and leaf blower call for varying mixtures. All get 40:1.

I can't fathom new equipment being destroyed by using 40:1.
 
Originally Posted By: cpjr
I was able to find some trufuel 40:1 fuel on a clearance sale. My Echo equipment calls for 50:1.

I just wanted to verify my calculations were correct.

40:1 trufuel would have 128 oz fuel and 3.2 oz of oil.

32 oz of this mix would be 31.2 oz fuel and .8 oz of oil (40:1)

To make this mix 50:1 I would need to add 8.8 oz of 4 cycle fuel, which would give me 40oz of fuel, with .8 oz of oil.

Does my math look correct ? My Echo deal swears up and down that the 40:1 fuel will damage the echo trimmer ? I don't know that I agree, but he is the one that would be doing any warranty service I may need for the next 5 years.

thanks


Yep, your math looks correct.
40:1 would probably work OK, though. The negative consequences of too much lube is not as bad as the negative consequences of too little lube.
 
Originally Posted By: Shrubitup
Dirt bike gets 32:1 so all other OPE whether 2 or 4 cycle get same. No issues.


That's what I do with the 2 stroke stuff atleast. None of them really smoke either, unless I richen the carb too much. For whatever reason, I don't like the smell of my ATV or riding mower burning premix gas, its wrong somehow. Almost like the smell of 2 stroke motor getting burned up from running to lean...
 
There is a danger to having to much oil in the mix. The fuel system adds X amount of fuel/oil to x amount of air. From this mix of oil/fuel/air only the fuel and air burn. The oil is formulated to resist burning and do the job of lubricating. This is why you see blue smoke and not black. Adding oil effectively reduces the fuel/air mix and leans out the fuel/air mixture. If gone to far, a lean mixture can lead to detonation. Not a good thing.
 
Originally Posted By: IndyIan
Originally Posted By: Shrubitup
Dirt bike gets 32:1 so all other OPE whether 2 or 4 cycle get same. No issues.


That's what I do with the 2 stroke stuff atleast. None of them really smoke either, unless I richen the carb too much. For whatever reason, I don't like the smell of my ATV or riding mower burning premix gas, its wrong somehow. Almost like the smell of 2 stroke motor getting burned up from running to lean...


My OPE is not as diverse as yours. Push mower chain saw line trimmer and a pressure washer.
 
Originally Posted By: dave123
Just run the 40


This is what I do too.Done so for many years.
 
If the fuel/air ratio of a machine is so close to the edge that going from 50:1 to 40:1 could cause a to lean ratio and possibly lock up the engine, then using said engine in temp swings from say 80*f to 40*f would cause even more damage from lean ratio.

Btw, Ive never seen a 2 stroke engine seize up, burn down, or whatever from using to much oil. The only way I could even fathom it happening is if the fuel/air mixture is so screwed up to begin with that it's the jettings fault and not the oil anyway.

I own many 2 stroke engines, including some high Hp machines. The only engine that I actually measure the oil ratio in is a high dollar 200hp engine. And that's only because I add 10 gallons of fuel at a time. And even at that it is never exact, it's just "close enough"
Everything else, like weed wackers and chainsaws get a splash of oil with their fuel.
One more BTW, the 2 stroke oil that I use in every engine is $15 per Gallon.
 
Originally Posted By: Srt20

One more BTW, the 2 stroke oil that I use in every engine is $15 per Gallon.



Which 2 stroke are you using?
 
Status
Not open for further replies.

Similar threads

W
1996 Ryobi String Trimmer
Replies
5
Views
314
Whimsey
J
VP Pro-Max 50:1
Replies
8
Views
3K
Nukeman7
Speedbird001
Small OPE victory
Replies
4
Views
448
tmorris1
oil pan 4
Running 40:1 in a 50:1 world.
2 3 4
Replies
67
Views
16K
dirtymudder
D
Thoughts on synthetic fuel for small engines (mower, chain saw, trufuel, vp racing)
Replies
14
Views
2K
ARB1977
Back
Top Bottom