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John Lancaster

do I need to filter mogas?

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I would like to start using 91+ auto gas in my CTLSi, for all the obvious reasons. Mechanic at my field said it's no problem, even with ethanol, as long as it doesn't sit in the tanks too long. He then suggested that I filter the gas with chamois cloth before using it. I tried this yesterday--lined a funnel with chamois and poured from one jerrycan into another. The problem is it took forever--the gas flows at such a trickle that it would have taken me an hour, literally, just to fill a single five-gallon can. Obviously not a viable solution.

My questions:

1. Is it really necessary to filter auto gas?

2. If so, is there a better way to do it?

Thanks for any advice.

 

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I haven't for 20 years. You have filters in your fuel system. If auto fuel isn't clogging up all our millions of cars I don't think it will bother our engine. Some do like to filter all their fuel and that's okay. It's a personal preference. Your gas station has in line filters.

 

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About the chamois. It's been years since I did this but I remember something about gas only flowing in one direction through a chamois. We did it to keep water and debris out when refueling from cans in remote areas of Alaska.

So, if you really see a need to do this, try turning the chamois over.

Otherwise, do what the rest of us are doing.

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1 hour ago, sandpiper said:

About the chamois. It's been years since I did this but I remember something about gas only flowing in one direction through a chamois. We did it to keep water and debris out when refueling from cans in remote areas of Alaska.

When I was working at Evergreen up there, that’s exactly what we ended up doing in the field.

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I guess I am the outlier.  I do filter my Auto Gas.  I bring in fuel in 5 gallon cans, and pour them into a gas buddy (25 gallon fuel container) that I have modified to pump fuel using compressed air.  I run it through an inline fuel/water separator and filter.  It is probably way overkill, but it does put my mind at ease.

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I have a CTLSi.    I stopped filtering or using ethanol free a couple years ago.  So far no issues.  

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I've used MoGas with 10% alcohol for last 10 years.  I buy from large, clean gas stations and the only filtering I do is when the fuel goes thru the coarse screen at the bottom of my funnel. Never had a problem and my gascolator screen never seems to have dirt or foreign debris at the yearly inspections.

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After much research, I am burning 100 LL avgas + additive.  It is more expensive per gallon, the oil changes are 2X the frequency (every 25 hrs).  The upside is that I am supporting the airfield, the 100LL gas doesn't stink up the hangar the way Mogas does, most airports sell 100LL, I am not humping gas cans up the ladder with my bad back... and, Rotax officially approves 100LL.  Just plain easier.

 

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After getting some questionable gas one time from a local station, I now run mogas through a Mr. Funnel as I pump into my gas cans.  I don't know if it's actually doing any good, but it's some peace of mind. 

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15 hours ago, AGLyme said:

 the 100LL gas doesn't stink up the hangar the way Mogas does, 

I have the plane plus 3 mogas vehicles in my hangar/garage and don't smell gas unless it is coming out the gas cap and vent. I think I would smell 100LL under the same circumstances.

Maybe my nose isn't sensitive to those smells?

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Two A&P's I spoke with told me that they always know when a customer has Mogas (instead of 100LL)... they come into the shop in the AM and the shop smells of... Mogas.  100LL, never.  Sounds real to me.  Thanks, Andrew

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Av Gas has a different smell. I don't like the smell of car gas, though I will say the 91-93 octane fuel doesn't smell as bad as the cheaper grades in my opinion. I don't like getting it on my hands, because the smell remains even after washing my hands. Av Gas while it does dry the skin out, doesn't have that lingering smell.

I really dislike the smell of Jet A.

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On 2/23/2019 at 9:35 PM, AGLyme said:

After much research, I am burning 100 LL avgas + additive.  It is more expensive per gallon, the oil changes are 2X the frequency (every 25 hrs).  The upside is that I am supporting the airfield, the 100LL gas doesn't stink up the hangar the way Mogas does, most airports sell 100LL, I am not humping gas cans up the ladder with my bad back... and, Rotax officially approves 100LL.  Just plain easier.

 

Your gearbox rebuild interval is also cut by 40% (from 1000hr to 600hr) and you will get lead deposits in the valve train as well, which may or may not have performance implications as well as an effect on whether the engine reaches/surpasses TBO.  Even if you use Decalin or another scavenger to displace the lead, it still ends up somewhere, and when exiting the engine can cause brittleness in the exhaust which can lead to exhaust system cracks. 

Personally, I think 100LL is "just plain easier" in the short term, but harder and more expensive in the long term.   How a fuel smells doesn't enter into my decision making.

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On 2/23/2019 at 9:35 PM, AGLyme said:

After much research, I am burning 100 LL avgas + additive.  It is more expensive per gallon, the oil changes are 2X the frequency (every 25 hrs).  

 

I usually use 100 LL.  I have not used any additives.  Maybe I should look into that and start?  Recently I found an airport in the area - KGBR, Great Barrington, Massachusetts - that sells 94 octane MoGas.  I filled up on Saturday there for $5 per gallon.  Also one could use this site to find other places:  http://www.flyunleaded.com/mapusairports.html  I'd probably use auto-gas from a regular gas station but I am not supposed to per the terms of the hangar I am using, so I don't.  

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Hi EFB. I also get 94UL from there. Nice people. 

But it has been hard to pass up the ethanol free fuel for under $3 in my area at the local gas station.

(To find ethanol free fuel, use the app PureGas) 

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Kent, thank you for that App... around me, the lawn mower guys are selling Ethanol free by the pre-packaged gal for $30... I did note months ago that the GB Airport pumps the 94 MoGas... a bit of hike from Chester though.

Ideally, I want to get a Rotax Rating and be able to change the oil myself merely for the convenience of it, as opposed to dropping the plane off at a busy Rotax center.

Does anyone know how a mere civilian like me can get Rotax training?  I won't touch the Annuals, etc... just the oil changes.

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7 hours ago, EFB said:

I usually use 100 LL.  I have not used any additives.  Maybe I should look into that and start?  Recently I found an airport in the area - KGBR, Great Barrington, Massachusetts - that sells 94 octane MoGas.  I filled up on Saturday there for $5 per gallon.  Also one could use this site to find other places:  http://www.flyunleaded.com/mapusairports.html  I'd probably use auto-gas from a regular gas station but I am not supposed to per the terms of the hangar I am using, so I don't.  

EFB, while the lease has already been signed, if the airport has taken any federal dollars in the past (I don't know how many years back) the airport administration can not (usually) prevent you from bringing in and using your own fuel. They can prevent you from storing that fuel in the hangar (my lease specifically addresses this), but the airport authority can not prevent you from fueling your own plane with your own fuel as long as reasonable precautions are taken.

This talks a little about it.

https://www.faa.gov/airports/resources/publications/orders/compliance_5190_6/media/5190_6b_chap11.pdf

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Thanks for posting the link.  I contacted my Senator’s  office last week and some kid couldn’t come up with anything.  I was told that the airport in my town (TCL) has stopped people from self fueling.   Now that I have the rules I can get to the bottom of it.   First thing is to ask the “wet behind the ear airport manager” for a copy of the Self Fuel rules.  He will probably look at me dumbfounded.  

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