[f-AA] Stromberg updates

[Mark Peterson]

Just got off the phone with the good folks at Mike's Aircraft Fuel Metering Service in Tulsa , OK and had a good conversation with the tech. Some notes:

Mogas doesn't seem to worry the carb, IF you run the carb dry at the end of the flight.  So our common practice of running the engine to exhaustion with

fuel shut off is good for the carb.  MoGas probably needs to be run through the carb every four weeks or so, to keep it from gumming things up, so fuel

shut off stops are good to empty the bowl and keep things going well.   (Of course, every few stops, shut it down with the P-lead after a few seconds

with the fuel shut off to make sure those little pesky wires are still holding hands with the mag.)  Keep away from bad MoGas and your OK.

Needle Valve.  They normally just replace them and lap the new ones them at overhaul.  They will wear and after 4 hours or so, even a new laped one will

do a drip.   It's steel on steel, so no alarm.  The rubber ones got age hardened, the derlin ones didn't work, so we are left with steel.  If the factory

was still in business they would probably have a new rubber compound for the new fuels, but with a 70 year old carb, we're just lucky to have parts.

Bowl erosion.  I had heard of the bottom of the bowl being eaten away with ethanol, so I asked.  Mine was fine.  The problem is usually crud and water

sitting in the bottom and he hasn't seen too many bowl issues.  Again, if you shut down the carb with the fuel shut off and drain it if you aren't

going to use it with the drain plug, not usually a problem.

Float:  The pivot is replaced at the overhaul to prevent the sticking float issues. Just routine.  They get sticky and worn after a while.

Rearranged vent: The service bulletin calls for a yellow dot on the outside of the carb, but the recent overhaul manuals did away with that. 

So you can now have the mod done without the yellow dot on the outside of the carb.  The vent is moved up to the throttle body area for

taildraggers.  Again a routine thing to do at overhaul.

They estimate the idle speed by turning in the screw to bottom and then out two turns.  Mixture is also estimated.  You have to field adjust them when its

installed.  Mixture is judging how the plane goes from idle to main jet about 1200 rpm or so and also when you shut down at idle, if the rpm goes

up when it's on it's last gasp, it's could be a bit rich.  You can't really exactly do the mixture exactly on the Stromberg, so if its running fine, good enough.

I usually ask the mechanic to set my idle at 550 or so when it gets installed.  Hand propping does that for you.

They quoted four weeks and they were right on getting it done then, even with a record snow storm.  At the price they quoted. 

Upper and lower installation gaskets included.   Yellow tagged but no sticker for the logbook.  You have to write that up.  Donna is the woman in

the office and she does good work for them.   Their business  with the Strombergs have definitely seen an uptick with the

hospitalization of the other business who worked on them.  http://thestrombergspecialist.com/index.php   Hope he's OK and there's still

good information on the carbs on his website.

Home [thestrombergspecialist.com] Specialists in "Grand Champion" restorations and overhauls of Stromberg NA-S3 aircraft carburetors thestrombergspecialist.com

That's the update.   Mine was a good normal overhaul, first time it had been gone through in decades.  Carb is starting its

journey home today.  I insured for 1K  on the shipping.

Hope that helps someone in the future.  OF course, all information is through my ears and not to be considered

as legal facts from Mike's.

Mark

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[Richard Murray]

Mark-

Were there any issues with your carb or you just felt it was time for a check-up?

What kind of dollars should one expect for a normal overhaul?

Richard in OH who has a Stromberg or two that haven't had a physical in some time.

[Mark Peterson]

My slow dribble turned into drops every second or two when the plane was starting up.  I was turning on the fuel to do the

check at the gascolator and then turning the prop over a couple of times with the dripping and then turning the fuel

off to do the preflight and then starting it and returning to the cockpit to turn it back on.  That worked great, no primer

needed. If I forgot to close the fuel valve then it took a lot of prop blades to clear the engine.  It dripped for

about 15 seconds at that point.  Flooded for sure.

The IA at the annual said it looked like it was running rich and so time to send it off.  And when I turned the fuel

on to show him, it literally was a dripping flow.  It was getting embarrassing to see the asphalt on the taxiway get

gas stains on it every time I started it up.  And you know, it's those staring at the ceiling at night

thinking about what could possibly go wrong with the plane that finally gets to you. . .

Mikes quoted $650, which was less than the other shop that does it. Your experience might vary,

as they say.  A fair price in my estimation after my home airport charged me $440 to replace

a mag rotator- without the cost of the part which I supplied.

Mark

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From: aer...@westmont.edu <aer...@westmont.edu> on behalf of Richard Murray <murra...@gmail.com>
Sent: Wednesday, March 24, 2021 10:12 AM
To: aer...@westmont.edu <aer...@westmont.edu>
Subject: Re: [f-AA] Stromberg updates

 

[Richard Murray]

Thanks Mark. That indeed seems like a very fair price for an overhaul.

[Rick]

Did I miss the price? 

A I also wonder why they feel the delrin needle doesn’t work. 

Thanks, Rick Dover 

Sent from iPhone

On Mar 24, 2021, at 1:40 PM, Richard Murray <murra...@gmail.com> wrote:



[Mark Peterson]

It too breaks down and ages out.  Just takes a little longer than the rubber one. 

The service history of it made them just produce the steel ones.

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From: aer...@westmont.edu <aer...@westmont.edu> on behalf of Rick <rdo...@mmr-inc.net>
Sent: Wednesday, March 24, 2021 10:58 AM

[Dan Vandermeer]

Dwight

I warned you that Mike is treasure trove of info on legacy tube and fabric singles. Here is his post on the outcome of his Stromberg overhaul.  

Dan 

Sent from my iPhone

[Duane Fey]

Does anybody, from this forum and in California, run car gas in their Aeronca?  I’m interested in the idea of running a tank through it, every now and then, to clean up the lead deposits, but I’m very hesitant to do so. 

Duane

‘46 Chief, N85981

On Mar 24, 2021, at 10:04 AM, Mark Peterson <mrpet...@msn.com> wrote:



[Mark Peterson]

Literally I’ve run nothing but MOGas since I started to fly 86E in ‘95.   As long as you find a non-ethanol source it’s good.

Sent from my iPhone 

On Mar 24, 2021, at 6:28 PM, Duane Fey <duan...@gmail.com> wrote:



['Ken McClelland' via aeronca]

I don’t currently have an Aeronca flying but a friend mixes non-ethanol with 100LL regularly - around here it’s called REC 90. Recreational fuel 90 octane.

Ken

Sent from my iPhone

On Mar 24, 2021, at 9:28 PM, Duane Fey <duan...@gmail.com> wrote:



[Mark Peterson]

But California could be a tough case.   Try https://www.pure-gas.org/.   

California is pretty limited.  Live in a farm state in the Midwest no problem, it’s almost on very corner.

Sent from my iPhone 

On Mar 24, 2021, at 6:28 PM, Duane Fey <duan...@gmail.com> wrote:



[Duane Fey]

Ok, I misunderstood the original message.  I thought they meant it would be OK to run regular card gas, provided you ran the carb dry, because it kept the ethanol from sitting in the bowl. The only sources for clean MoGas are more expensive than AvGas. 

Thanks,

Duane

‘46 Chief, N85981

On Mar 24, 2021, at 6:37 PM, Mark Peterson <mrpet...@msn.com> wrote:

 But California could be a tough case.   Try https://www.pure-gas.org/.   

[Mark Peterson]

Sorry, ethanol is terrible under any circumstances.  They were talking about gumming up the carb with all the paint thinner type chemistry that's

in gasoline now.   Car gas is meant to be used, not stored, so if it's sitting in the plane for more than a month it can lead to issues.  Ethanol, the

idea that buys votes in Iowa. . .

Mark

 

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From: aer...@westmont.edu <aer...@westmont.edu> on behalf of Duane Fey <duan...@gmail.com>
Sent: Wednesday, March 24, 2021 6:45 PM

To: aer...@westmont.edu <aer...@westmont.edu>
Subject: Re: [f-AA] Stromberg updates

[Harvey Brock]

    Duane,

         Since I got my Champ, I’ve been running ethanol-free car gas. The owner before me and the owner before that ran ethanol free gas as well. It’s understandable that I haven’t had issues because I fly more hours per year than previous owners. The owner before me flew about 5 or 6 hours per year according to the logs. 

        If non-ethanol fuel was going to be a problem, I would think it would have already shown itself by now.  The A75 in your Chief only got 100LL while in my possession. I can’t tell any difference except the price.

Harvey, who flys 100LL in the Cherokee, non-ethanol in the Champ and regular unlead(10%) in the gyro

Get Outlook for iOS

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From: aer...@westmont.edu <aer...@westmont.edu> on behalf of Mark Peterson <mrpet...@msn.com>
Sent: Wednesday, March 24, 2021 10:40:21 PM

[Andy Lumley]

Excellent information here and I know that at some point I should bite the bullet and get mine done. I've had the plane for 31 years and knock on wood the carb still works OK, not great when less than 25f out, have to advance the throttle very very slowly.

I've never used any ethanol, always been mogas and occasional avgas, had the needle stick on me once but it fixed itself. I never run the bowl dry but surely not a bad idea.

-Andy 

[Rich Dugger]

I have run nothing but mogas in my 172 since 1985 and nothing but mogas in both Champs in have owned since 2000.

There is no reason to be putting lead into your tank to foul your plugs.

[Andy Lumley]

What about the lubrication that leaded gas offers, I thought that was a positive?

[Rich Dugger]

Lead is added to gas to increase the octane rating and foul your plugs and make your valves stick.

These little engine do not need the octane increased.

[Richard Holcombe]

And to stop the erosion of valve seats.

['Botijo G' via aeronca]

That was my thought exactly!

[Rick]

I thought the same until  I listened to the EAAwebinar by Mike Bush on why valves stick. It has more to do with Lycoming engines than ours but since we can’t control mixture it affects our little engines too. Quite long, but worth the time. 

Thanks, Rick Dover 

Sent from iPhone

On Mar 25, 2021, at 6:28 PM, 'Botijo G' via aeronca <aer...@westmont.edu> wrote: