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Old Apr 28, 2009, 05:53 PM
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u2builder's Avatar
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What fuel for OS MAX 91 FX GLOW ENGINE 2 STROKE

The manufacturer says: REQUIRES: Fuel: 18% (minimum) conventional lubricant content and 5%-20% Nitro

What does "conventional lubricant" mean. Does it mean castor oil or non synthetic.

What would folks recommend to break it in? How much fuel to break in?

What fuel would folks recommend running?

Thanks.
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Old Apr 28, 2009, 06:49 PM
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Melbourne, Australia
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Conventional lubricant would mean castor or synthetic or a mix of both.

Break it in on what fuel you intend to use and follow O.S break in procedures. All of this should be in the manual. Make sure you use the recommended prop they suggest for break in.
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Old Apr 30, 2009, 02:17 AM
TigreJohn
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Would highly recommend not using a fuel that is all synthetic lubricant. With it, you have much less wear protection on a lean run. Castor oil has a significantly higher burn temperature than synthetic. True, repeated lean runs with castor lubricant can lead to varnish deposits. But varnish is much easier to remove than to replace the aluminum on the piston.
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Old Apr 30, 2009, 05:52 AM
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We can only get synthetic oil fuel where I am. All the guys at my club run all synthetic fuel. If you know how to tune an engine and always tune to the rich side of peak rpm then you won't need the castor oil as you will never run lean.
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Old Apr 30, 2009, 10:13 AM
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The 91 FX is a ringed engine so I'd highly suggest using a fuel with a lot of castor in it. My running in fuel for ringed engines has 25% all castor but then I get castor very cheap here in Adelaide. It's just as cheap in Melbourne too panzerd 18, $8 a litre as I recall .
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Old Apr 30, 2009, 10:37 AM
Sippin' on Kool Aid
Long Island NY, USA
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If you can get coolpower fuels, use there 20% blend. its the pink stuff. thats all i run in my engines and they run great!

also try wildcat fuels 20% blend. great stuff.
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Old Apr 30, 2009, 08:56 PM
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Downunder if you mix your own but all the prebought nitro fuel is all synthetic from the hobbies stores near me.
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Old May 01, 2009, 05:45 PM
TigreJohn
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Panzerd18: you can get castor oil at a pharmacy (its also a laxative). Or do you call it a dispensary in OZ? Also check with a motorcycle shop who deals in racing. Be sure to ask for the oil that mixes with alcohol just in case what they have is a blend.

I have regularly added castor oil to ANY fuel that is less than 22% oil since day one and I still have engines that I bought in the 70's with lapped meehanite pistons that still have excellent compression that I fly regularly. In your situation, I would recommend adding 200ml of castor oil to a litre of 18% oil content fuel to bring it up to 22%. Your engines will last much longer.
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Old May 01, 2009, 08:23 PM
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Quote:
Originally Posted by jjkupinski
I have regularly added castor oil to ANY fuel that is less than 22% oil since day one and I still have engines that I bought in the 70's with lapped meehanite pistons that still have excellent compression that I fly regularly. In your situation, I would recommend adding 200ml of castor oil to a litre of 18% oil content fuel to bring it up to 22%. Your engines will last much longer.
While there's no harm in raising the oil percentage to 22%, there's also probably no benefit.

Higher than necessary oil contents result in poorer engine performance, reduced flight-time per tank, greater mess and even harder starting in cold temperatures.

Your engines may have lasted a long time with 22% oil but I've got engines here with over 400 hours running on them using just 12%-14% oil and they show no signs of significant wear, pulling as strong now as they did when new.

Too much oil is simply throwing money down the drain unnecessarily (IMHO).

In fact, if you work out how much it's cost you for all that extra oil since the 1970s, you'd probably find that if you'd used less oil and saved the money you'd spent, you'd be able to buy a couple of *brand new* engines (and the old ones would still be running just fine).

Just because a little is good doesn't mean that more is better.
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Old May 01, 2009, 11:32 PM
TigreJohn
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Don't you just love those naysayers who use the word "probably". An ounce of prevention is worth far more than a pound of cure.
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Old May 02, 2009, 07:26 AM
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Quote:
Don't you just love those naysayers who use the word "probably". An ounce of prevention is worth far more than a pound of cure.
Well, when someone uses Probably they are putting a qualifier on their statement, rather than asserting what they say is absolute fact. And in the discussions of fuels and lubricants, I'd say Probably is a good word to use!

It's very interesting how much opinions vary on glo fuels. Some folks swear by synthetics; others by castor oil, and still others by various mixes. Personally, I kind of like the idea of some castor in that it doesn't burn off and supposedly protects against a lean run and maybe also prevents corrosion better. On the other hand, I am a new to the hobby old duffer, and at my Club they use only Cool Power Synthetic (expensive high nitro heli fuel of all things) and give me ...... when I bring fuel with castor in it. I do have to say that when they are done flying their planes aren't covered in goo. Who the heck knows how long their motors last but many of these guys have many years in the hobby. Still, I'll probably continue to run some percentage of castor oil, 30 to 50% maybe, just to Probably be on the safe side.
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Old May 02, 2009, 11:32 AM
Sippin' on Kool Aid
Long Island NY, USA
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All i can say, is that this is a somewhat pointless argument. People at my field have engines that are as old as I am (20) that are still flying and havent adjusted their oil content in the fuels at all. They run them hard and they run great. Everyone should do what they feel, whether or not its spending extra money.

As for u2builder, i say just buy a gallon of coolpower 20% blend, and go fly. I'm flying one of my buddies plane with the same engine using regular coolpower 20% fuel and it has 2 gallons through it and is running strong. no problems b/c there is less oil. just fuel it up, start it, let it warm up then tune it to peak performance..
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Old May 02, 2009, 11:51 AM
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Does Coolpower 20% refer to 20% oil or 20% nitro?
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Old May 02, 2009, 04:04 PM
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Tokoroa
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20% nitro -- it has (I believe) 18% synthetic oil.

Do a search for "cruel power" here and see what turns up :-)

The reality is that during its lifetime, an engine will burn many, many times its own value in fuel so a penny saved here and there on fuel costs can pay for a new engine in a surprisingly short amount of time.

My philosophy when switching to a lower oil percentage was that by using less (but better quality) oil, I could save enough money in fuel costs to buy a new engine within a couple of years -- so who cared if my engines wore out more quickly.

The reality is that my engines *haven't* worn out but I *have* saved a bundle. What has happened is that my engines have run better, given more power, used less fuel and suffered absolutely no ill-effects.

But the great thing is that we (well, most of us) live in a free country so we can run 50% oil if we want to -- it's a personal choice.
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Old May 03, 2009, 11:36 AM
Sippin' on Kool Aid
Long Island NY, USA
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Quote:
Originally Posted by u2builder
Does Coolpower 20% refer to 20% oil or 20% nitro?
20% nitro and 18% oil as xjet said.

again, i run this stuff in all my engines (even four strokes where the manual suggested 20% minimum oil content) with no ill effects. as long as you tune them good, they don't care.
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