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-   -   how do you tell if you have bad fuel (http://www.rcuniverse.com/forum/glow-engines-114/2967766-how-do-you-tell-if-you-have-bad-fuel.html)

outbackdean 05-12-2005 07:51 AM

how do you tell if you have bad fuel
 
How do you tell if you have bad fuel or bad ingredients eg -- Nitro , coolpower oil or methanol ??
I believe something is wrong with my fuelmix but how do I tell which one is to blame out of the three.
MY MIX IS 15% NITRO 20%OIL 65%METHANOL
I mix my own fuel because there is no retail outlets where I live the closest is 600km away.
I have been flying for 14 years with out ever having any trouble with any engines then or of a sudden all I get are dead sticks or my motors do not want to spin the prop that they where spinning before and the same rpm(can not get the same performance out of them.
SO BACK TO THE QUESTION HOW DO YOU TELL WHICH ingredient IS NO GOOD ?

Thanking you for any assistance
Outbackdean --Manually Fix-- Outback dean Outback-dean Outbacker Outbacks Outback Outback's Outbroken Unbacked (outback OZ)

w8ye 05-12-2005 08:26 AM

RE: how do you tell if you have bad fuel
 
The usual problem is the Methanol has absorbed water? If there was a lack of acetone or other stablizer, you wouldn't be able to get the needle set. It would be one click too rich or too lean.

Enjoy,

Jim

bako 05-12-2005 08:30 AM

RE: how do you tell if you have bad fuel
 
u are adding some aceton in fuels? [X(][X(][X(]

ampa 05-12-2005 10:06 AM

RE: how do you tell if you have bad fuel
 
the engine stop when you cut the current to the plug/can run only at full throttle/overheats/and of course poor performances

downunder 05-12-2005 10:22 AM

RE: how do you tell if you have bad fuel
 
Like Jim said, usually the only thing that can give a problem is if the methanol has absorbed a lot of water from the air. Does your homebrew have much the same nitro content as whatever you were using before? If not, did you retune for the difference? Have you tried another plug? Why do I have a mental picture of you flying from the top of Ayer's Rock? :D

blw 05-12-2005 10:00 PM

RE: how do you tell if you have bad fuel
 
Good to hear from someone mixing their own fuel.

Do you cover your fuel when sitting in the sun? I always put mine in the shade. Do you put your fuel in the same jugs every time? Maybe try new containers with a new mix.

outbackdean 05-13-2005 04:41 AM

RE: how do you tell if you have bad fuel
 
Hi
yes I have tried new plugs even different plugs(different heat ) and new mixes of fuel in new containers.
My engines have always run very very good with the same recipe that I still use,
But now for the last two months I have nothing but trouble with all of my motors.
They can run great on the ground but about half way through the flight they will start to run off Like they are all of a sudden over propped ( to large of a prop dies when you pull up hard )then when you drop back to idle to land the engine will quit will not idle for a approach.

If there was water in the fuel would it show up if I put a sample in the freezer overnight as ice particles ?

Thanking you for your assistance
Outbackdean (outback OZ)

ps I fly from a claypan 3km out of Broken Hill NSW we have a local club here with about 10 or so flyers but no one else uses 15% nitro the most they use is 5%

Rupurt 05-13-2005 05:18 AM

RE: how do you tell if you have bad fuel
 
The water is unlikely to freeze. Check with your methanol supplier they may have supplied you with a different grade that they thought was a suitable replacemet(if the usual grade was unavailable), not knowing the application.

w8ye 05-13-2005 05:42 AM

RE: how do you tell if you have bad fuel
 
The alcohol is hygroscopic and the water and alcohol are dissolved within each other. The water will not freeze out. If you get the mixture cold enough, it will turn to a slush but will not separate. The oil will get stiff before the slush situation occurs.

You would have to distill the alcohol to get it out of the water.

Enjoy,

Jim

Rupurt 05-13-2005 06:12 AM

RE: how do you tell if you have bad fuel
 
Distilling won't get the water out, you can only distill methanol to 96%.

w8ye 05-13-2005 07:41 AM

RE: how do you tell if you have bad fuel
 
I knew you couldn't get it all out but I thought you could get more out than that? -sorry.

Enjoy,

Jim

delman 05-13-2005 07:49 AM

RE: how do you tell if you have bad fuel
 
Even if they use 5 percent - ask to use some of their fuel - it will answer the question about your fuel.


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