Dogpilot, sure happy that you don't have any lead issues with 7 to 1 compression engines. We are fortunate here in the Midwest that two kinds of gasoline come up the pipeline from the refinery-----84 and 91 octane. All the different things at the pump are based off of them. We have summer and winter blends and I agree a certain octane can be made up all kinds of different molecules. I think in the winter I can actually smell propane in a gallon sometimes. The most consistent part of the fuel is the ethanol assuming it is in the fuel to begin with. Just about all of Iowa stations still have 87 pure gas that is a blend of 84 and 91 and of coarse some places sell the straight 91. Word travels fast around here so not much of a chance somebody doctors the fuel. Seems to me I remember reading years ago that 100LL in the Pacific Northwest was different than 100LL made in some other part of the country and that caused problems too.

Did you pull carb heat when you did the 180 back to the airport? If so did it do anything?

I’d say carb icing, if it’s pouring fuel out like a sieve with the fuel on and engine off, it’s a stuck or sunk float.

Edit to add, did the old fart who rebuilt the carb set the float level correctly?

A too high afloat setting will give you the Stromberg drip, meaning it will drip fuel out the air box it’s annoying, you just have to shut off the fuel valve. but shouldn’t affect the way it runs.

Those carbs are stupid simple.

dogpilot wrote:Kind of like sex without protection, eventually you may get a surprise.

My wife & I had unprotected sex twice during our child bearing years and have three kids. Not kidding.

AKJurnee wrote:Did you pull carb heat when you did the 180 back to the airport? If so did it do anything?

Yup, I did pull carb heat with no improvement and even checked the icing probability when I got home. 50 degrees 45% humidity and the dew point was 29. Icing was possible, but not likely. It was fuel coming out of the airbox, but a slow drip, not like a sieve.

AKJurnee wrote:Edit to add, did the old fart who rebuilt the carb set the float level correctly?

Never met him, but he sounded like a old fart and certainly gave me a good tongue lashing on the phone. I have no idea if he set the float level correctly. Maybe I do have the Stromberg drip. Sounds like something I may have contracted on the 70's and it's just showing itself now.

Zzz wrote:This is why I recommend tasting all fluids that emanate from your airplane.

Hammer wrote:The biggest surprise to me would be that I was having sex..

I almost spit my beer all over the table when I read those.

Thanks,

Pete

Sticky, stuck valve, or bad plug(s), shitty mags.

Assuming “old fart” rebuilt the carb using the correct jets and parts for the A-65, with a full rich setting the engine should run fine at WOT. Even with the wrong jets for a C-85 it should run fine without a drop in power.

I say something else is going tits up. Anything from bad induction leaks (those hoses go bad) to a bad cylinder, and rarely a bad lobe on the camshaft, or crappy mag timing “e-gaps”

These engines are more basic than a lawnmower engine, todays mechanics are worse.

So I figured a followup would be in order. I flew the Champ this afternoon for the first time since I had the issue. It ran flawlessly. It does seem like mo-gas was the culprit. I talked to my mechanic ( an older guy that has re-built and flown multiple Champs and Cubs with a 65hp Continentals and a Stromberg carb.) several times and had another guy with lots of experience with those carbs look at it. We did not take the carb off, although we did check the fuel lines for leaks, took the gascolator off and checked the induction hoses. We drained the tank, and carb and re-filled with 100LL. I then did multiple static runs over several days (the last couple tied to my truck) and it ran fine. On their advice I climbed in and flew above the airport for the better part of a hour. Full throttle, half throttle, idle, carb heat, all of the above. Pulled redline easily in level flight, never wavered or stumbled and idled just fine. Problem solved? I hope so, but in the mean time I will be sure to stick close to the strip. Thanks for all the input. If there is any more info., I will be sure to pass it along.

Pete

Glad it worked out, Pete. I'm not sure I would call it a solution though, because you're limited to 100LL. Wasn't the change in needle and seat that would allow you to run car gas an option?

I don't see the problem with car/mogas. I do see a problem with a carburetor with parts so delicate.

Zzz wrote:Glad it worked out, Pete. I'm not sure I would call it a solution though, because you're limited to 100LL. Wasn't the change in needle and seat that would allow you to run car gas an option?

I don't see the problem with car/mogas. I do see a problem with a carburetor with parts so delicate.

Thanks Zzz, I hear you, but for now I am happy running 100LL. It's a bit of a pain since the nearest airport with it is 40 miles away, but I borrowed a transfer tank and just got 70 gallons, which at 4 gph should last quite a while. I have learned a bunch the last couple of weeks. I am not sure how much is accurate and how much is B.S., but most of it seems to makes sense. From talking to people that know these carbs, apparently the floats are sensitive to the different densities of fuel and are tough to set for both. Also, the reason the needle tip is not metal is that back in the day it was tough (or more likely more expensive) to get a good fit between the needle and seat with the machining technology available if they went metal to metal, hence the plastic tip. I think you can get new seats and needles with metal tips, but it doesn't sound like many shops use them. I am not sure why. So apparently these carbs are pretty bombproof when using the correct fuel, but are susceptible to leaks when not. So for now it's 100LL and I will keep looking at options.

Pete

Glad your back to flying.

The Stromberg we had on our Luscombe was set up to run either mogas or 100LL and did so for years without issue. When we overhauled the engine the carb came with a neoprene tip needle. During the first year it developed the Stromberg drip so when annual time came our IA asked if we had plans to run mogas in the future. We did so he installed a metal tipped needle and made a float adjustment. That was the last time the carb was touched during the 10 years I flew that airplane.

-0-

Well said Dogpilot.
Lots of folks don’t realize that you can minimize the expense of avegas by stretching out your oil changes.