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4 stroke fuel

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JC12/07/2009 19:48:26
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Hi Guys
 
Ive just got a SC52 4 Stroke from a club mate. I have had  some  advice with regards to which fuel to use. I use Cool Power 5% nitro in my SC40 2 stroke and a couple of guys at the club say that this fuel has insufficient oil for a 4 stroke. On reading up on the subject I found an artical on the net suggesting that 4 strokes need less oil than a 2 stroke. Is this the case? How do I work out how much oil content a fuel has as there is nothing on the fuel bottle of my Cool Power giving the oil %. Only the nitro %. as usual all advice welcome.
 
Regards Jon
winchweight12/07/2009 20:19:03
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I use cool power 10% without issue.
ken anderson.12/07/2009 20:21:31
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hello jon-one of member's used to use his 2st fuel for both engine's-2st and 4st---he used to say that it was ok(and they used to run ok)but he used to say that he couldn't run his 2st on any 4st fuel as it had to much oil in..........so to sum up i think i'm right in saying that your 4st need's more oil than the 2st----as the 4st get's the oil second hand so to speak after the combustion process-not like the 2st that get's it straight away on it's way up to the piston / plug etc...apparentley that's why they are(4st) libel to corrosion more easly than the 2st's because the oil they get is full of the acid's etc after the big bang upstair's......hope all that help's/make's sense....
 
 ken anderson........

Edited By ken anderson. on 12/07/2009 20:21:52

JC12/07/2009 20:42:37
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Shaun, ken
 
Thanks guys. One of the guys did say that I should use 10% nitro on a four stroke but it would run on 5% ok,  so thanks for confirming that for me. I got a bit concerned when someone mentioned dedicated 4 stroke fuel. What is different about 4 stroke fuel is it just a higher oil content? I still dont know how you work out how much oil content a fuel has as there is nothing on the canister stating the oil content.
 
Thanks
 
Jon
ken anderson.12/07/2009 22:06:46
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jon-18-20% oil in 4st..........use straight fuel- no nitro/it's cheaper....
 
       ken anderson.....
Andy Green12/07/2009 22:42:56
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For what its worth, I run all my engines (2 & 4 stroke) on Prosynth 5% and so far have never had a problem.
 
These include Saitio 180, OS FS 70, SC70, Justengines 56, Supertigre 45 & 75.
 
I believe (anecdotally) that a lean engine run will cause more damage than a slightly lower / higher  than recommended oil content.
 
Andy
andy watson12/07/2009 23:02:28
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For a 4 stroke you need 18%+ oil.  The nitro % depends on how/what you are flying- but it doesn't need to be much normally.
JC13/07/2009 11:42:09
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Thanks guys
 
Still dont see anywhere on the canister labels the oil contnet of a fuel. Just gives the nitro %.
 
Jon
andy watson13/07/2009 12:38:39
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It often says on the label, or describes itself as 4 stroke fuel.  I suggest a look at the manufacturers web site if it doesn't
Myron Beaumont13/07/2009 20:28:20
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I use "Model Technics Duraglo 5 "for all my engines . No problems ever ! 2 st & 4 st !
Stick to what you think is best I reckon & what you can get hold of easily  ,-Don't believe everything you read or hear about . That's life though isn't it ?
Always used castor oil based fuels for 50 years . Years ago I added a "drop" of Castrol "R" --Just for the smell --Same as in my Gold Stars  petrol .
Pure nostrilgia
JC13/07/2009 20:52:00
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Very many thanks guys
 
Myron I think you hit it on the head. Every one has a different opinion as to what is the best fuel,model,engine,radio ect. The guy I got the engine off ,Kurt, has been flying for years and said that I would have no problems using the cool power 5% that I have for the 4 stroke. I can understand why as the whole right hand side of the fuz and the right wing is covered in oil after even a short flight with the SC.40 I have fitted at present. 
 
Again thanks to all happy landings
 
Jon
Phil Claridge14/07/2009 09:26:22
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i'll second myron, been using duroglo 5 since 1995 on all engines no problem
Steve Hargreaves - Moderator15/07/2009 09:08:06
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Hi Jon.....some useful data here concerning fuel. Just Engines reckon a few percent less oil in a 4 stroke.....I guess because they are under less stress than a 2 stroke (only half the "bangs"!!)
 
Personally I use Southern Modelcraft Mo-glow fuel in all my engines...2 & 4 stroke. 15% synthetic, 2% castor & 5% nitro. A bit of nitro helps with the throttling/idling on a 4 stroke.... Remember to always tune a little bit rich on the ground.....peak the motor & then unwind the needle a few clicks....always trade a bit of smoke for a few hundred rpm....your motor will love you for it, run cooler & last longer.............!!!
JC17/07/2009 22:12:38
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steve
 
Thanks very much. i have got some Mollenburg 4 stroke fuel with 15% synthetic(we dont get castor over here) It was recomended by one of the more experienced guys at the club. You say tune a bit rich. What is a bit rich? how many turns out from fully lean is normal for a 4 stroke?
 
Thanks again
Jon
Steve Hargreaves - Moderator19/07/2009 14:06:37
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SC motors would normally be around 1.5-2 turns out on the needle......start her up & let it warm up at a fast idle for a couple of minutes....tune for max revs & check it still holds its revs with the nose pointing vertically then open up the needle about 4-5 clicks....you may need to adjust the idle needle to get a good tickover/transition.
 
If you have an expert on hand get him to show you...4 strokes have a less easily defined "peak" than 2 strokes so its a little bit harder to judge....a lot comes down to experience I'm afraid....
Bladerunner18/08/2009 10:54:56
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Posted by Steve Hargreaves on 19/07/2009 14:06:37:
SC motors would normally be around 1.5-2 turns out on the needle......start her up & let it warm up at a fast idle for a couple of minutes....tune for max revs & check it still holds its revs with the nose pointing vertically then open up the needle about 4-5 clicks....you may need to adjust the idle needle to get a good tickover/transition.
 
If you have an expert on hand get him to show you...4 strokes have a less easily defined "peak" than 2 strokes so its a little bit harder to judge....a lot comes down to experience I'm afraid....

 As you say, and thats why a tacho is very handy on 4 strokes. Helps find peak quite accurately and helps to reference prop performance.

Edited By Bladerunner on 18/08/2009 10:55:14

Brian Cooper18/08/2009 17:27:46
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Just use Prosynth.    Job done.  
 
B.C.
Bladerunner19/08/2009 19:50:11
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Posted by Brian Cooper on 18/08/2009 17:27:46:
Just use Prosynth.    Job done.  
 
B.C.

 And that has how much oil in it as per OP's query?...

Brian Cooper19/08/2009 21:09:03
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Posted by Bladerunner on 19/08/2009 19:50:11:
Posted by Brian Cooper on 18/08/2009 17:27:46:
Just use Prosynth.    Job done.  
 
B.C.

 And that has how much oil in it as per OP's query?...

 Don't know.  And don't care.
 
Frankly, we don't need to know.   eg: I have never asked for a chemical breakdown of ingredients before I refuel my car.
 
All we need to know is the fuel (Prosynth) works....... and wow, it works extremely well.
Engines run faster, cooler, last longer and stay clean.  In other words, it does what it says on the tin.
 
B.C.
Martin McIntosh19/08/2009 23:43:12
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Re oil content. For what it is worth, YS fuel contains 23% synthetic. I run my `cooking` engines on Model Technics contest 10 which I believe has 17 or 18% oil including 2% castor. I also use a similar blend from Southern Modelcraft and have had no problems whatsoever, so I would say that you only require a high oil content for the more powerful motors, but would never use less than 17%. About time that this is stated on the container which I believe has been asked for before on this forum but as yet has not been responded to by the manufacturers. Wake up!

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