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Lycoming R-680 Experience

phdigger123

FRIEND
Cottage Grove, Mn
I was out flying my Gullwing today and had an adrenaline raising experience. It has a Lycoming R-680-13. You can use full power for one minute on take off and then you need to pull the power back. On a go around I went to full power. When I pulled the power back after about 45 seconds the engine damn near quit. The carb heat was off at that point. I went back to full power and pulled on the carb heat and the noise came back. When I landed I did a run up and everything seemed normal. So, my question is, do any of you have much experience with this engine and is it susceptible to ice? It was about 60 degrees outside with some light haze. I don’t know what the dew point was.

Any help or guidance is appreciated.

Thanks,
Mike
 
Are you using 100LL? Mine didn't like non-aviation types of gas.
Possible small amount of water in the carburetor bowl. Drain/Flush the bowl.
 
I also had a loose distributor finger causing a cutting out issue. Your description does not match that.
 
Not much R680 experience, but with the R985in the Howard, you ran carb heat to keep carb air temp at 32 degrees C.


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I'm almost positive that I never had carb ice in the 100+ hrs behind the R680 in the Stearman. Temps between 40f - 90f. I say that because the carb heat hardly worked, maybe move the needle on tach .001 when applied.

Glenn
 
None of the 680's I have flown had a carb ice issue, sounds like fuel delivery or mixture. Check it over good, if you don't find anything get another set of eyes on it. These things don't quit for no reason.
 
Try a full power run up and check the RPM for max. Recommended. Also I’d check every fitting and connection in the full system , to make sure no air is getting in where it shouldn’t..that would be from the fuel tanks to the cyl. Head.
 
I am trying to picture the induction system again... but my bet is on carb ice. I had a Taylor craft that used to do the same thing when running mo-gas- build ice even at full power.

as I recall, I owned a V-77, she did develop carb ice and required the carb heat at all times. A little moisture in the fuel, plus moisture in the air-haze- and it coming back on with heat really indicates an ice situation.

I also would spend time looking everything over, but don't be surprised if it comes down to ice.

Post a picture of your bird, I really miss my old bird!
 
I am trying to picture the induction system again... but my bet is on carb ice. I had a Taylor craft that used to do the same thing when running mo-gas- build ice even at full power.

as I recall, I owned a V-77, she did develop carb ice and required the carb heat at all times. A little moisture in the fuel, plus moisture in the air-haze- and it coming back on with heat really indicates an ice situation.

I also would spend time looking everything over, but don't be surprised if it comes down to ice.

Post a picture of your bird, I really miss my old bird!

All we ever ran was mogas, 13 gallons an HR

Glenn
 
All we ever ran was mogas, 13 gallons an HR

Glenn
Glenn,
I always thought that ought to be true since these engines have been around long before we had good avgas. When I took the Bamboo Bomber to Greenville they were out of 100LL and only had something for boats. I have no idea what it was except they were using it. Since these engines had been around since the early 30s burning anything, I filled up for the trip home. While climbing out I noticed a different color to the exhaust trail behind the plane. This was accompanied by a distinct non-avgas smell in the cabin. All went well until I was passing east of Boston over the water, both engines suddenly quit cold. I pulled both carb heats and they ran again. That was a very long few seconds! At least I was on floats and could have landed anywhere.
The next day I decided to fly off the rest of that ugly gas. When I pushed up the power to get on the step, both engines hesitated and would not come up to power until I pulled back the throttles and slowly pushed them back up. Then they ran OK. I took off and burned off one tank until they coughed. Landed and topped off the empty tank with 100LL, then took off again to burn off the other tank. Once that Greenville gas was burned off and replaced with 100LL, there never was another issue. 100LL for me always after that. I figured that they came up to power in Greenville OK because they still had 100LL in the carbs and fuel lines.
 
Just for fun, put a gallon of 100LL and a gallon of premium mo-gas in a freezer over night.

The next morning pour each through a filter funnel and tell me what you see.

Makes a believer out of most folks. We filter our sled fuel here even when 10 degrees out because of the moisture content. Almost every 5 gallon can has ice in it every fill up.
 
Just for fun, put a gallon of 100LL and a gallon of premium mo-gas in a freezer over night.

The next morning pour each through a filter funnel and tell me what you see.

Makes a believer out of most folks. We filter our sled fuel here even when 10 degrees out because of the moisture content. Almost every 5 gallon can has ice in it every fill up.

Is that with Ethanol or pure gas?
I had nothing but problems when Ethanol came to town. I drive older cars and none of the rubber or other fuel components will withstand that crap.
I discovered that when I bring home a 5er of crap gas I add a little bit of water and let it sit. Does not take long till the water gels at the bottom and I can then pour off the gasoline for use.
This works even better in the winter since the crap will be a frozen lump which once you pour off the real gas, leave the near empty jug in the sun and then pour off the crap.
Beats trying to get the crap out of the vehicles fuel systems.

We now have a stable supply of pure gas around here and I have never had a moisture issue with it.
 
Just for fun, put a gallon of 100LL and a gallon of premium mo-gas in a freezer over night. The next morning pour each through a filter funnel and tell me what you see.Makes a believer out of most folks. We filter our sled fuel here even when 10 degrees out because of the moisture content. Almost every 5 gallon can has ice in it every fill up.
Ethanol is a sponge disguised as a liquid

Glenn
 
Glenn,
I always thought that ought to be true since these engines have been around long before we had good avgas. When I took the Bamboo Bomber to Greenville they were out of 100LL and only had something for boats. I have no idea what it was except they were using it. Since these engines had been around since the early 30s burning anything, I filled up for the trip home. While climbing out I noticed a different color to the exhaust trail behind the plane. This was accompanied by a distinct non-avgas smell in the cabin. All went well until I was passing east of Boston over the water, both engines suddenly quit cold. I pulled both carb heats and they ran again. That was a very long few seconds! At least I was on floats and could have landed anywhere.
The next day I decided to fly off the rest of that ugly gas. When I pushed up the power to get on the step, both engines hesitated and would not come up to power until I pulled back the throttles and slowly pushed them back up. Then they ran OK. I took off and burned off one tank until they coughed. Landed and topped off the empty tank with 100LL, then took off again to burn off the other tank. Once that Greenville gas was burned off and replaced with 100LL, there never was another issue. 100LL for me always after that. I figured that they came up to power in Greenville OK because they still had 100LL in the carbs and fuel lines.

You got the premix ;-)

Glenn
 
1F981C38-AF62-44D8-84A6-26ED3803FCC8.jpeg3CBCFE51-43CD-4AB9-BF33-B918676BB683.jpeg829C3566-9A31-4759-AD59-B8961264734B.jpegAktango58, per your request here are some photos of my V-77.
 

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Beats trying to get the crap out of the vehicles fuel systems.
I know someone that pours gas with crap through a Mr Funnel and hasn't used the quick drain for years. Also, this person wonders if carb heat is even necessary with the anti icing properties of crap.
 
Not sure if this is right but been told that the Alcohol is also used to increase the Octane so if you it collects water and is then removed so apart of the Octane rating is reduced. I have NO proof at all.
 
Not sure if this is right but been told that the Alcohol is also used to increase the Octane so if you it collects water and is then removed so apart of the Octane rating is reduced. I have NO proof at all.
Correct it raises octane, it also leans the mixture. If the fuel was 92 or 93 oct and you take the alcohol out you loose a point or two.
If you are flying an engine rated at 80/87 on 91 oct fuel, is there an issue, even if you are running 89 regular with the alcohol drawn out of it. That will still run an O-360 that is rated for 80-87.

If you want to gamble that your carb float, tip of the needle if it is the rubber type, fuel lines and other parts can withstand the alcohol, go for it.
I won't.
 
I agree and don’t run auto fuel either. In Alaska all the fuel is alcohol free but still don’t want any part of it. Most flying in my region of AK is near sea level but crossing the Alaska Range I got into a wave and ended up at 13,500’ and really didn’t need to worry about vapor lock, etc..
 
I don’t have anything productive, but I’d love to have some 680 experience - especially in that beautiful gullwing!
 
Makes me homesick.

Beautiful. Mine had blue accent almost identical to your red.

If you ever need a ferry pilot, let me know. I loved flying that bird!
 
I found some junk in the carb bowl when I drained it. I ran fuel through the carb one quart at a time until no more particulate came out. I did 3 more rinses with no more junk. Cleaned the finger screen in the carb and the gascolator. The finger screen and gascolator didn’t have any particulate in them. So I wonder how the junk got in the carb bowl. A few of the particles were magnetic. The rest felt like sand. I would guess I got out close to a teaspoon of junk.

I flew it this morning and it has never sounded better. I used plenty of carb heat to make sure there were no icing issues. I am going to drain the carb bowl again in a couple of hours and check for junk again.

Here are a couple of pictures of the junk.

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I had a fuel starvation issue in my old C170 ragwing years once.
As you may know, this model has an engine driven fuel pump.
Some stuff clogged up the inlet screen at the card.
It made it past any strainer at the fuel tank outlets,
and the screen in the gascolator,
and the very fine screen in the fuel pump.
FWIW it was very small red fibers--
made me think that someone had left one of those red shop rags
in a fuel tank and it dissolved over time.
 
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