N

Norman CYYJ

Well Known Member
How many of you are using straight mogas in your RV and what size engine do you have? And what troubles if any are you having? What octane are you using?
 
I ordered an ECI OX-340S. One of the reasons that I chose this engine is that it comes with 8.3-1 compression ratio. The guys at ECI said that Mogas work just fine in this engine.

Ryan
 
I burn 90 octane non-ethanol in a IO 320 Lyc. with on problems. Did check with Bart at Aerosport first.











Bruce 9A
 
it burns fine in a O-360 w/ low comp pistons.

The etoh messes up the capacitance fuel guages. They will read double.

I always used the 93 octane mogas.

But I have switched to av fuel now.
 
Superior IO-360 and I burn 91/93 octane (depends on how one rates it, but basically premium autogas) without ethanol. Compression 8.5:1. Works just perfect so far - 300 hours. I do put avgas in when traveling.

greg
 
I have heard that you have to adjust the timing (from 25 btdc) when using auto fuel, is this true?
I have a Thorp T-18 with an O-320 E2D 160 hp and would love to use mogas but have been afraid to take the plunge. It is great to see this topic !
 
Some States (in the USA) that have laws requiring ethanol in the gas also allow ethanol free gas at wholesale 'fuel farms'. A little extra shopping around, like a visit to the local 'Card Lock' or "Commercial Fuel Network" member distributor could work for you like it did for us. Our CFN FleetWide card is good at over 28,000 fueling sites.
Try: www.cfnnet.com go to the site locator and see if one is near you. Give them a call and ask about the gas.
I carry a 55 gallon drum and a fillrite pump in my truck. The local fuel farm is only a mile farther on the way to the airport, and the price is a little higher than ethanol blend fuel, but the car goes farther down the road per gallon about proportional to the price. The airplane (Cessna 182) loves the stuff.
I know it's not an RV as specified in the first post, but I also know many of you are worried about ethanol blended gas, and this is a way I found to get ethanol free unleaded regular and unleaded premuim mogas in Western Washington.
 
I have an O-360, 8.5:1 pistons, that uses 91 octane mogas locally and 100LL when on the road. I have no concerns about the ethanol blended fuel. 3 1/2 years and 625 hours with no detectable problems. Dan
 
I just started running Mogas 91. It's widely available at surrounding airports with no alcohol. I wanted to wait until I passed 100 hours on the engine before I switched. One thing however, I did have to change my timing on my p-mags.

MOGAS
P-Mags NO Jumper installed
max climb CHT 440+
max cruise CHT 415

AVGAS
P-Mags NO Jumper installed
max climb CHT 415
max cruise CHT 400

MOGAS
P-Mags Jumper installed
max climb CHT 410
max cruise CHT 380

AVGAS
P-Mags Jumper installed
max climb CHT 400
max cruise CHT 370

DISCLAIMER:The above numbers are approximate and no scientific calibrated test equipment was used to gather the numbers, neither was there a professional test pilot and team of engineers. It was just me and my Dynon Skyview
 
I have an RV 9 O-320 150 HP,,the engine doesn't mind autofuel at all, however, I used the rubber gaskets on the fuel senders and the autofuel made them swell and leak, I sealed them with the proseal tank sealer when I installed them but it didn't stop the autofuel from attacking them. I wish I had only used the fuel tank sealant as gasket material but I had that part done before I read all the post that said to discard that gasket and proseal the senders on the tank. This is the only problem I have had with autofuel.
Running avgas now until I can get rid of the sender gaskets that came with the kit.
 
Yes

E10 Premium with 10% ethanol. IO360. Been runnng ofr about 500 hours

Runs just fine but a little slower uses about 0.5 gallons per hour more to use E10 than striaght mogas.

Note I carefully selected all my fuel system components to be ETOH friendly.

I don't run a mechanical fuel pump for example.

Apparently striagh mogas is available locally I might check that out.

Frank
 
Leaning ?

I installed a fuel pump cooling shroud and a return line to the tanks on my fuel injected OX-320 with 8,5:1 compression. After running in the engine, I want to switch to 97 octane Mogas. I am still trying to find out how to get it without ethanol, because there is still a few rubber items in my fuel system that I am not sure of, regarding Ethanol friendly. (as 170 driver mentioned, the fuel sender rubbers, for example.)

The timing issue has already been mentioned, but what about leaning, LOP ?

Regards, Tonny.
 
LOP

It runs perfectly fine LOP..thats where I always run my engine.

Oh I have PMags and did not have to adjust the timing either.

Frank
 
Frank,

Several gas stations in the valley carry the ethanol free 92 as does the FBO at Lebanon. One of our FBO's here at Independence will probably have it soon. Also Mark Nelson Oil products in Salem. I think they also have a store in Albany or Corvallis but I'm not certain.
 
Thanks

I'm told Oberson oil here in Corvallis carries it as well..I will try a tank in each win and see which works out to be the cheapest to run.

Frank
 
SHIPCHIEF said:
Some States (in the USA) that have laws requiring ethanol in the gas also allow ethanol free gas at wholesale 'fuel farms'. ..., and this is a way I found to get ethanol free unleaded regular and unleaded premuim mogas in Western Washington.
Click to expand...

There are only four active mandatory E10 states and Florida will join them at the end of the year. Washington is a mandatory volumetric ethanol state which requires at least 2% of all gasoline sold be ethanol. Every mandatory ethanol state has an exemption from ethanol blending for aircraft use, however none of these states has any statute guaranteeing that ethanol free gasoline must be made for these exceptions. In all of the rest of the states, you are on your own.

Overall it makes no difference if you live in a mandatory E10 state or not, all of the gasoline will be E10 by the end of next year. If you want to know why www.e0pc.com. If you are a pilot and want to do something about it, www.flyunleaded.com If you don't start agitating soon, you can kiss ethanol free gasoline good-bye in this country.
 
160 hp carb- 320, premium non-alcohol mogas for the last few years with no problems. I tried regular mogas in a previous plane with the same hp engine & cht was a bit higher than I liked.

This is a plane that I bought already flying. I've avoided alcohol because I'm too lazy to check for/change rubber parts in the gascolator, etc. Note that when I was a much younger and dumber student pilot, on another plane I failed to check for alcohol & it dissolved the gascolator gasket, completely plugging the screen.

Charlie
 
Hi all,

Here is my logic:

I run about a 30-50% Mogas mix in the same tank.

Loads of people said to me do not use Mogas and an equal amount said don't use Avgas due to lead etc. So I thought stuff this and decided to go the less than 50% route. That way, ethanol should not be an issue and likewise lead should be good enough to lubricate but not too much to foul. It also suits my desire to procrastinate and choose a third option when presented with two.

Think that is logical?
 
For some reason, a Cessna Pilots Association newsletter found its way into my in-box. Call it divine intervention if you will, but some of it is pertinent to and touches on subjects already in this thread. I've excerpted comments between Mike Busch and a member.

"Tetraethyl lead in fuel provides zero benefit to anything other than as an octane enhancer. In all other respects, it's awful stuff and will not be missed once it goes away. TEL does not prolong exhaust valve life. There is absolutely no evidence that exhaust valves longevity is impaired in engines that run on unleaded autogas. The notion that lead is essential for exhaust valve life is an old wives' tale dating from WW2 when valves, guides and seats were made from much more primitive materials than they are now.
Mike Busch, CPA Tech Rep.

Mr. Busch,
Thank you for your opinion and if I may challenge your thoughts:
1. 100LL. If we agree the lead has been replaced, should I advance, retard or let stand the timing? {A brief background of how I got to this point} After a recent overhaul of a 320 H2AD I flew it aggressively to break in the chrome cylinders. The valves became very stuck and the top of the pistons were eroding. After reaming the valve guides, I took it upon myself to drill out the main jet for more fuel. This lowered the CHT and EGT on take off and when I got to altitude I could lean as usual. I was very happy. Then I noticed that the CHT remained low and the EGT seemed high. As I was questioning the fuel I advanced the engine timing by 3 degrees. This raised the CHT to where it could exceed 380 degrees and lowered the EGT to say 1200 degrees. This improved performance. The "ping" was my next question. I then contacted Electronics International and I talked to Dave Cambell and Ron (the boss) about building such an instrument and my reasons why. I also mentioned that one of the automotive suppliers had just such an instrument reading the resistance of the spark plug just after ignition. See http://delphi.com/manufacturers/auto/powertrain/gas/ignsys/ionized/ This is a good read.

2. RPM control. While flying to Aspen I had to descend from 13K to 7,800 (Sardy field). While descending on the "Nose Bleed one arrival" it occurred to me that this extended descent with the carburetor closed and the fixed pitch prop turning the engine at 2,000 RPM was crazy. Why not control the power like a Diesel engine does and reduce the fuel? The only noticeable difference was less breaking or slowing of the airplane by the engine and when some fuel was allowed to mix, a small popping or back firing occurred. I am not into back firing so I lean the engine to "off" with no backfiring.

This plane has much attention given to performance and can fly to 13K and 14K altitude when needed, 125K+ speed, and can burn as little as 7 GPH, full throttle. I am a very happy owner of a Cessna 172 As you might guess, I am in uncharted waters and so I wrote you......

Thanks again,
Bill

Bill,
Theoretically, the timing could be advanced slightly if higher octane fuel is used, because the combustion is slightly slower with higher-octane fuel. I say "theoretically" because adjusting the timing to anything other than exactly what's specified on the engine data plate is illegal. Advancing the timing 3 degrees will of course improve performance, but will sacrifice detonation margin. You can get away with it using 100LL in an engine certified for 80 or 91 octane, but it's absolutely illegal.

I absolutely agree with the concept of operating LOP and controlling power with the red knob rather than the black one. That's the way I operate my aircraft. I go to wide-open throttle at takeoff, and never touch the throttle again until just before landing."
 
guccidude1 said:
I have an O-360, 8.5:1 pistons, that uses 91 octane mogas locally and 100LL when on the road. I have no concerns about the ethanol blended fuel. 3 1/2 years and 625 hours with no detectable problems. Dan
Click to expand...

Dan,

Over the 3 1/2 years, about how much of the fuel used was E10?

Do you have a mechanical fuel pump on the engine?
 
Of the 625 hours, I would estimate 450 hours. Obviously, it is difficult to find mogas on the road, but I try. Yes, I do have a facet pump and the engine mounted pump. I have noticed that when I am using 100LL, I can lean a little more, noticeable by observation of the mixture control. Dan
 
170 driver said:
I used the rubber gaskets on the fuel senders and the autofuel made them swell and leak, I sealed them with the proseal tank sealer when I installed them but it didn't stop the autofuel from attacking them.
Click to expand...

that is soley because of the ethanol in the fuel.
 
it works for me!

IO550-N in my F1Evo. 100LL in one tank; premium MOGAS in the other. I figure there is E10 in the MOGAS, but I don't make any adjustments when switching. I see no difference in FF, EGT, or CHT. I operate LOP regularly as this engine is designed to work that way. 8.7 comp.; mags set at 22 BTDC.

I make dang sure I switch back to the 100LL tank on approach to the destination in time to get all the MOGAS out of the FI system before I power back in the pattern. 100LL is used for all ground OPS, and of course take-off and landing. This precaution is due to the uncertainty of the RVP of any MOGAS, no matter what time of year it is.

It has worked for me just fine. YMMV.

Carry on!
Mark
 
Ethanol in Mogas

Mark & Normand in YYJ
For your info

'' I figure there is E10 in the MOGAS''

Here in Canada,a friend of mine called the Technical Lab of Shell, Esso and Ultramar a few weeks ago and ask the head chemist if there was any ethanol in Mogas in Canada and his answers were than there might be up to 10% Ethanol in Regular Unleaded gaz but that it was impossible to get the High Octane level in Premium MOGAS if they used Ethanol ( I will assume it is the same in the USA. ) so it will be a safe bet to say that there is no risk in using ''PREMIUM Mogas'' in our engines.

Everytime I checked there wasn't any..

Bruno Dionne
[email protected]
 
Hey Mark-

I thought the 550-N was 9:1 compression. Did you lower the compression so that you could run mogas? How many ponies is your 550 putting out in the Rocket with the 8.7 pistons?

Can't wait for the F1 to go back into production.
 
http://pure-gas.org/
this has been posted elsewhere but i am putting it in here also. it is nice finding non ethanol gas if you want it. add to the list if you can. this pic was taken at Ksfq sw of norfolk VA.
img0083v.jpg
 
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RV-4 said:
Mark & Normand in YYJ
Here in Canada,a friend of mine called the Technical Lab of Shell, Esso and Ultramar a few weeks ago and ask the head chemist if there was any ethanol in Mogas in Canada and his answers were than there might be up to 10% Ethanol in Regular Unleaded gaz but that it was impossible to get the High Octane level in Premium MOGAS if they used Ethanol ( I will assume it is the same in the USA. ) so it will be a safe bet to say that there is no risk in using ''PREMIUM Mogas'' in our engines.

Everytime I checked there wasn't any..

Bruno Dionne
[email protected]
Click to expand...

This makes absolutely no sense to me whatsoever. Ethanol has a very high "octane", actually AKI (Anti Knock Index) but low energy. People throw out all kinds of numbers, but it is way over 100 octane. All types of mogas in the U.S., regular to premium is made at the E10 level. Ethanol at the 10% level will boost the AKI by about 3 points so regular E10 is made with a suboctane blending product called BOB (Blendstock for Oxygenate Blending) that is 84 AKI and the result is finished 87 AKI regular. Similarly 88-90 AKI BOB is used to make premium E10. This is why ethanol free premium unleaded in the U.S. is disappearing, the refineries make nothing but BOB when their geographical service area goes E10 and it is happening all over the country. By the end of next year all of the gasoline in the U.S. will be E10, it has to be because of the unintended consequences of the federal RFS mandate in EISA 2007. www.e0pc.com Canada is next, your government just passed a mandatory E5 law and BOB will spread.
 
So why not just use a mix of upto 50% Mogas? That way you get cheaper fuel, less lead but don't have to worry so much about ethanol etc.
 
F1Boss said:
IO550-N in my F1Evo. 100LL in one tank; premium MOGAS in the other. I figure there is E10 in the MOGAS,...
Click to expand...

That is a very dangerous assumption. If the mogas is E10, you should notice that there is never any water when you sump the tank. If there is "water" when you sump, you are in big trouble, the E10 has "phase separated" and you have unknown stuff that is corrosive in the bottom of your tank and some kind of gasoline of unknown specification most likely suboctane. It is irreversible so the tank must be drained and cleaned out and what you drain out is a hazardous material in most parts of the country. While it is permissible to use E10 or even Exx where xx is any ratio you want in a homebuilt, since you can specify it in your operating handbook that you wrote as the manufacturer of the aircraft, you better know what is in your tank and what the symptoms are when things go wrong, especially considering that aircraft fuel systems are vented to the atmosphere, unlike car fuel systems, and ethanol loves water.
 
Mixed bag with mogas

O-360, 7.2 compression pistons, and I use 87 octane ethanol free mogas as follows. For takeoff and landings, I use my my rite wing which has 5 gal avgas and the rest mo. My left tank is all mogas.

I experienced one issue with ethanol free mogas (no av mixed in). After the airplane sat in the hot sun before flying, the fuel flow sensor reported low fuel pressure just after takeoff when the electric fuel pump was turned off. By keeping the electric fuel pump on, pressure went back up. After 15 minutes of flying, fuel pressure was OK with the electric pump off. We deduced that 15 minutes of flying cooled the mogas fuel.

After that experience, I started mixing av into the mo and this has not occurred again.

The second experience was with mogas that had ethanol in it (Big Mistake). After takeoff (cooler day), we went out to practice engine-out. After a long descent, the engine almost stalled when I put in power. It may have been carb ice even tho carb heat was on.

After the subsequent landing, the O-360 stalled on the runway. This Superior engine has NEVER stalled.

The remaining ethanol fuel was drained out of the airplane.
 
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Purely personally

I wouldn't be using any ethanol with a mechanical FP unless I was sure the diaphram and seals were compatible.

Secondly the RVP of any kind of mogas is higher than Avgas and is at greater risk of vapour locking. Not saying I wouldn't use mogas in this situation but I would want to make sure the VL lock isue is taken care of.

As for me without a mechanical FP (IO360) (electric only pumps in the wing roots) and an AFP system..I can say that E10 is not a problem and has never acted any different to pure mogas..excet you need to burn a little more to go the same speed.

So the fuel in itself is not an issue, in 500 hours or so I never seen any water in the tanks or phase seperation (flown in IFR in the winter at 15,000 ft etc). A mechanical fuel pump sucking up hill is a marginal solution however.

Frank
 
Ethanol in Mogas

Hey Dean..
Thank you for your comments as you seem to know what you're talking about but please don't shoot the messenger would you, I was just mentioning info that was pass on to me..:eek:

Also for your info, I no longer use Mogas in my RV-4 unless I can get ( confirm ) Mogas from an Airport fuel suply...

The day that I won't be able to afford the required fuel in my airplane will be the day it will be for sale..

Regards

Bruno
 
More info than the human mind can comprehend...

Anyone interested in really finding out everything there is to know about ethanol in aircraft engines, try plowing through 282 pages of this report.

http://www.easa.europa.eu/safety-an...cellaneous/Final_Report_EASA.2008-6-light.pdf

But try not to fall asleep doing it. The chart that depicts risk factors on a scale from zero to 1000 is mind boggling. Fortunately, most of risk "issues", and there must be a hundred of them from paint coming off the wing near fueling ports and falling into the tank to water separation, are in the 150-200 range. A few are in the 800-900 range.

Just the size of the report is enough to get your attention but how much real world application is there is questionable. The report does acknowledge they could find only one accident report in the entire NTSB data base that is related to ethanol and it is not conclusive.

By way of useful information, the Rotax 912 is approved for E10 fuel. I read it in one of their SI's this morning.

I also read this morning that Missouri mandated E10 at all retail outlets in 2008. But E10 labeling is not mandated. They exempted 91 octane fuel from ethanol but it to is not mandated. So what that means is there could be 91 octane fuel available with no ethanol but it is a secret since labeling is not required nor is ethanol in the 91 mogas - but it may be there. Walmart labels say fuel "may" contain 10% ethanol.

Confused? Welcome to the world of ethanol politics in the midwest.

I ordered an ethanol test kit this morning and will test 91 mogas locally to see what gives. If any comes up clean, I will use it in my engine. At this point I am chicken about running ethanol through the mechanical pump. Tempest informs me they are testing materials in the Lycoming pump to be FAA approved for ethanol but the process is ongoing and it will be some time before all the work is completed.
 
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RV-4 said:
Hey Dean..
Thank you for your comments as you seem to know what you're talking about but please don't shoot the messenger would you, I was just mentioning info that was pass on to me..:eek:
> ...
Bruno
Click to expand...

I understood that you were passing along info from supposedly knowledgeable sources and certainly didn't mean to imply you were wrong. I was just astounded that anyone in the petroleum industry didn't know that ethanol was used as an "octane" enhancement and I have never heard anyone say that it was impossible to make premium unleaded E10 because of the ethanol. As Mr. Spock would say, "That isn't logical".

The crux of the problem is that the refineries will stop making premium unleaded gasoline and there will be no source for Petersen high compression STCs and Rotax 100 HP engines. It will all be suboctane blending product. It has already happened in California and the Northeast.
 
Water in fuel

I would be interested in knowing if anyone with a regularly hangared airplane has found water in their fuel.

My RV-6A (purchased flying) has always been hangared except for the trip to Oshkosh this summer. It rained heavily at my stop in Hazen ND. In fact I had to stay on the ground an extra day.

Upon sumping the tanks I had water in the fuel on the right tank, but none on the left. I thought the right cap did not fit as tightly as the left. I replaced both, so the former left cap will be a spare.

Prior to this plane I had a Cherokee that was always hangared except on trips. Never sumped any water from a tank. I think the umbrella caps on a Cherokee probably do better than flush mount caps in the rain.

My conclusion: water gets in through caps that don't seal well. The advice about water condensing out of the fuel may be a myth.

I am certainly open to evidence that thermal cycling can result in water in the tank, but I currently remain skeptical. I also agree that it would be foolish not to sump tanks. There is probably just enough fuel in the carburetor and the lines for start-up and taxi. The first slug of water one would get is right after lift off.

LarryT
 
E-10 in "old" cars

I ran E-10 in my old cars back in the 80s & 90s.

These cars were never intended to use ethanol laced fuel.

In hundreds of thousands miles, I never experienced any degradation of fuel system components (fuel pumps, hoses, carb seals, etc).

I did, however, suffer from sudden engine stoppage from time to time.

Each time the engine would quit, I'd just wait a few minutes and then re-start and be on my way. Vapor lock no doubt.

I ground tested my -9A (low compression lyc) on car gas with 4-5% ethanol.

During a prolonged taxi test (I was trying to swing my compass), the fuel pressure went low. Engine still ran. Turning on the boost pump restored fuel pressure. Don't know if the cause of this was fuel but it has not happened again.

I've been flying the plane with a mix of car gas & 100LL. I ALWAYS test the car gas for % ethanol. Summer fuel around here runs about 4%.

A 50-50 mix yields about 2% ethanol. I don't think this will cause any problems.

I don't think I'll use the 10% stuff (winter fuel).

Saves a ton of money in the long run.

I notice that the small FBOs in the midwest often have mogas. I will seek out those places for re-fueling.

IMHO...:D

Dave
-9A flying
 
I have been trying marked gas here (91 octane mogas). After leaning the engine out on avgas and letting the engine stabilize I switched over to mogas. There was no change in the CHT or EGT and no power change. I tried this at low, medium and high power setting all at 2500ft. I then tried is again at 12,000ft and no changes. No vapour lock yet. No problems on ground operations. At $60 to $80 saving on fuel per fill up I think if there is no adverse effects I will be burning Mogas. I am flying an RV-7 fixed pitch with an IO-360.
 
alcohol in premium mogas

The statement about alcohol not being in Premium mogas is definitely in error, at least in Mississippi. Both of my 'clean' stations recently started adding alcohol; one of them hasn't yet placarded their pumps. I only use premium, & I always check.

Charlie
(found 2 other good stations, though...)
 
rv7charlie said:
The statement about alcohol not being in Premium mogas is definitely in error, at least in Mississippi. Both of my 'clean' stations recently started adding alcohol; one of them hasn't yet placarded their pumps. I only use premium, & I always check.

Charlie
(found 2 other good stations, though...)
Click to expand...

Maybe the statement is unclear.

Ethanol is mandated except it is not mandated in premium fuel. Premium fuel may or may not have ethanol. I suspect around here it is in all fuels due to lousy EPA air quality.
 
Where to find the good stuff

I didn't see the following info in any of the prior posts.

www.flyunleaded.com
www.pure-gas.org

Flyunleaded for airports selling premium mogas without ethanol.
Pure-gas for local fuel distributors selling premium mogas without ethanol.

Watch those prices - one nearby airport is selling 91UL for 10 cents more per gallon than their 100LL.
 
David-aviator said:
Maybe the statement is unclear.

Ethanol is mandated except it is not mandated in premium fuel. Premium fuel may or may not have ethanol. I suspect around here it is in all fuels due to lousy EPA air quality.
Click to expand...

It appears you live in Missouri. Missouri is one of the four active mandatory E10 states, except as you point out it is not mandatory in premium. However, the Missouri law has no statutory requirement that anyone has to make premium E0 gasoline. Same in all of the mandatory E10 states. The state legislators had no compunction about forcing you to use E10 and forcing the gasoline industry to install expensive ethanol blending infrastructure, but they didn't want to force the gasoline producers to make ethanol free premium if they didn't want to. But not to worry, it makes no difference anymore. All of the mandatory E10 laws will be swamped next year by the unintended consequences in the federal RFS mandate in EISA 2007, which is NOT a mandatory E10 law. All of the gasoline in the U.S. will be E10 by the end of next year. It has nothing to do with EPA air quality requirements which only affect a few urban areas anymore because gasoline and the pollution control systems in your cars are make your exhaust a lot cleaner.
 
Bob, keep one tank for avgas, the other for mogas and check for ethanol via Gerry Humphries method. Take off/land, taxiin on avgas and you should have no worries and l bet the inside of your engine will be a lot healthier. Watch that ethanol as Gerry found out climbing through 5000ft on a hot day!
 
EAA mogas webinar

If you missed this informative webinar the other night, watch it here:

http://www.eaavideo.org/video.aspx?v=651976925001

You'll learn that mogas is distilled from crude oil (in a process similar to an alchohol still) while 100LL is a blend of various chemicals.
I learned that while 100LL has an octane rating of 100, 91UL mogas is actually around 86 octane when measured on the same scale as avfuel. Mogas uses that R+M/2 formula when calculating their octane rating.
 
Thanks Steve

Thanks Steve,

Listening to the video while handing out Halloween candy.
 
frankh said:
I wouldn't be using any ethanol with a mechanical FP unless I was sure the diaphram and seals were compatible.

Frank
Click to expand...

The IO550 fuel system has no diaphragms, excepting the FP control in the pump (gear type pump). I will admit to the system having some shaft seals. AFP boost pump, so there are no problems there. Might be that the Silver Hawk FI system is almost a clone of the TCM system? Nowhere near as complicated as the Bendix or AFP fuel controllers, but than again I will be the 1st to tell you both are very brain dead systems, requiring the pilot to control the red lever much more than the other style systems.

Checked my 93UL when fueling last week -- looks like about 5% ethanol in it. Sure wish that this particular octane MOGAS was E-zero.

In the past I have tested to E40 or so -- no mods needed other than pushing the mixture full fwd. Higher percentages would likely need a larger main jet size due to the higher viscosity of ethanol, as the Vanguard Sqdn will tell you.

Carry on!
Mark
 
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