Bizarre problem, that's contagious...

[rosenkranswa]

Some years ago I started having an annoying problem with my '30 AA Stakebed. It would start fine with the GAV maybe halfway open, warmup allowing me to close the GAV down to less than a quarter open and idle nicely. But, when I got on the road it would act like it was way lean, and wouldn't run well until I openned up the GAV almost a full turn. Then I would have to leave it there with it running slightly rough at stop lights.

Tried retiming, cleaning and regapping plugs, reset point gap, cleaned carburator, checked for air leaks at the carb and manifolds; nothing seemed to work.

Just figured I'd have to live with it, then my '30 pickup started doing the same thing. Tried all the same remedies to no avail. The '29 Roadster was next, and now the '31 Woody. Same symptoms, same remedies, same outcome. The Woody is the worst, once warmed up I have to open the GAV almost a full turn to run, then when at a stop it runs real rough until I turn the GAV down to less than a quarter turn open, then have to open it again once I'm moving or it acts over lean.

I'm at a loss, what could be affecting all 4 vehicles the same way? Am I doing something, or are they all reacting to something in the local gas?
The '30 Town Sedan and both Model T's don't seem effected - yet. Ditto the early V8 and wartime Jeep.

[J Franklin]

Try the 1930 TS carb on the woody and see what happens. Do you always run fresh gasoline?

[Tom Wesenberg]

Are you using the 10% crap gas?

[stouchton]

I am in no means an expert on A's, but I do have the opinion and experience that the GAV should not effect idle unless the idle speed is turned up too high.

[Jon]

I'm with Tom, the only thing common besides the driver would be the gas you put in it.

[Dave in MN]

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Tom's right again.
Try removing the jets from the carb and spray carb cleaner through them, blow out with compressed air and then repeat 2-3 times. This will remove any build-up. Reinstall and test. I've seen this happen many times.
To complete this work, you do not need to remove the carburetor (if it is a Zenith) from the manifold. Just remove the lower section of the carb to gain access to all the jets. While you have it apart, remove and clean the brass well if it is a Zenith.
Good Day!

[tbirdtbird]

maybe an agent of the EPA would like to do field work and adjust all our carbs to account for the crappo polluted fuel they have crammed down our throats, and the resultant side effects such as gumming up the innards of the carb if the car sits more than a month or 2

my experience FWIW RE: GAV is that it can affect idle somewhat, at least in my neighborhood

I may be dreaming, but it seems I get a little extra bit of 'shelf life' out of the crappo gas since I began adding MMO to the tank for valve lubrication.

Tom W, what do you think?

[Purdy Swoft]

I think that its the gas also and recommend what Dave in MN says in post # 6 . The GAV does effect idle unless it is idling lower than I prefer to run mine. The low idle circuit is mostly for showing out at car shows and causes a spooling down effect that hinders gear shifts when idle is set that low. Most ain't gonna run on the low idle circuit when cold or especially if you are running any ethanol, STP gas treatment or other additive that causes the carb to act up . I also recommend Marvel mystery oil in the gas , especially if ethanol is present.

[mass A man]

I agree with Purdy wholeheartedly on this. One side note, I recently asked my local airfield about obtaining avgas, they won't do it. Planes only, no filling of cans or carrying off gas from the property. Price is $6.33/gallon.

[Mitch//pa]

well i dont have that problem and i use the same fuel as the OP.. i say put in a set of flow tested jets, clean and blow everything out and make sure the throttle shaft does not have play.. this has a direct effect on the GAV operation

[Tom Wesenberg]

My GAV does work on idle as well as high speed.

I always try to use real gas and always add 4 oz. of MMO with each 10 gallons. I think it's even more important to add the MMO if you have to use crap gas.

When I get caught up on the generator work I am going to try some gas experiments.

[Mike V. Florida]

http://modelabasics.com/carb%20basics%202.htm

[BILL WILLIAMSON]

I've known many guys that solved their "problems" by just dumping out old gas & refilling-----"WELL, IT DIDN'T SMELL OLD"!---Dumb Asses!
Bill W.

[Dave in MN]

Originally Posted by Mitch//pa

well i dont have that problem and i use the same fuel as the OP.. i say put in a set of flow tested jets, clean and blow everything out and make sure the throttle shaft does not have play.. this has a direct effect on the GAV operation

Mitch, You likely wouldn't have the problem if you drive your A often. I don't have the problem either because I go through a tank in less than a month but this gent has 4 A's and it is likely that they sit for awhile between use. That's when the problem develops. I use whatever gas is available during the summer because it is not in the tank long but over winter...non-oxygenated only and with a stabilizer.
Good Day!

[Mitch//pa]

Originally Posted by Dave in MN

Mitch, You likely wouldn't have the problem if you drive your A often. I don't have the problem either because I go through a tank in less than a month but this gent has 4 A's and it is likely that they sit for awhile between use. That's when the problem develops. I use whatever gas during the summer because it is not in the tank long but over winter...non-oxygenated only and with a stabilizer.
Good Day!

Dave,
my car is mainly showed and hardly driven. i go though maybe 3 tank fillups a season. with the proper jets the GAV is much more responsive both at idle and cruising. i think this will solve the OP problem along with no other vacuum leaks, and a tight throttle shaft and properly set up carb.

[rosenkranswa]

I actually try to drive each of the cars as often as possible, or my daughter does. Still, I think based on the responses its a problem with the local gas combined with needing to drive them more.

[Purdy Swoft]

With all due respect, people that say that they have no problems with ethanol adultrated fuel must be getting a fresher or different grade than we are getting here. I have used Stabil and I really can't tell that it helped at all. Ethanol gas ruined the carburetor on my weed eater, nearly ruined my power saws, ruined two fuel pumps in the Tahoe and had me pulling what little hair that I have left out with my model A's. I lose power with the corn fuel, If any of it remains in the tank or carburetor for much over two weeks it causes problems. It has bad effects on anything rubber. When used in my power saws it causes hesitation (won't take the gas untill it gets hot) and I have to use channel lock pliers to remove the gas caps. When corn gas is used it clings to the carburetor jets and will continue to cause problems even after changing back to real gas. I know what I'm talking about and this is the experience that we have had. The ethanol gas that we get here is so bad that If I couldn't get real gas I would just have to give up the model A's or ever using my power saws, weed eater or lawn mower . I recently bought a new Craftsman riding mower, the first question that I asked was if it had ethanol gas in the tank. The salesman quickly replied that it had real gas. They had several mowers on the showroom floor. Thank God that we have A Shell station that sells real gas at a pump around back, its a hassle because the pump isn't card frendly and we have tro go inside to pay first. We also have to pay a lot more but I really don't worry that much about that because I personally don't have to have that much.

I rebuild my own carburetors. I mostly only use original jets. My GAV works perfectly at idle and cruising speed .

[Mitch//pa]

to set the record straight i am by no means saying that i see no problems with ethanol. that stuff will actually eat through a metal in tank electric fuel pump etc. what i am saying is an improperly rebuilt carb or other issues will cause the problem lets not just blame it on the fuel alone. i have auction cars come into my shop that have sat for a year and the ethanol has locked up the pump and started to reak and around 2 years old it looks like a dark yellow piss.

[Old182]

FWIW, I agree with Mitch. Ethanol has been around long time and it's not going away any time soon thanks to an out of control EPA (but that's another issue). Because of the oxygen, ethanol "chemically leans" the mixture (reducing CO) so richening the mixture with the GAV makes sense. If your engine runs best a half turn richer than it used to, then do it. While most cars see no effect from 10% ethanol, 2-cycle engines inherently run rich and they seem to have the most problems with "crap gas". I add extra oil to my chain saws, weed whacker and blower to compensate for the leaning effect of the ethanol. I'd rather see blue smoke than replace equipment. We have the ability to richen the mixture on our Model As and should do so if that's what the engine wants. Regarding deposits on jets or other fuel system parts, alcohols are good solvents and would clean deposits not add to them. But fuel additives are very high molecular weight compounds (usually diluted with kerosene) - deposits you see may be the additive, not the ethanol. There's no magic in the real world - it's all chemistry. Besides, ethanol can't be THAT bad - Jack Daniel's is 45% ethanol. P.S. Mass Man: try another airport but have a wing number with you as there is no road tax on avgas and FBOs can't sell without one. Avgas is the best fuel you can get.

[Dave in MN]

Originally Posted by Mitch//pa

Dave,
my car is mainly showed and hardly driven. i go though maybe 3 tank fillups a season. with the proper jets the GAV is much more responsive both at idle and cruising. i think this will solve the OP problem along with no other vacuum leaks, and a tight throttle shaft and properly set up carb.

Mitch, I agree that the jets need to be correctly sized and the carb needs to be mechanically correct. We are suggesting the same thing...but I am suggesting cleaning your existing jets before moving to replace. Renner's jets are well worth the money if you do not flow test them yourself.

Regarding ethanol "enhanced" gasoline. My experience in working on other owner's cars is that if a car is stored for a period of time with ethanol gas, the jets will typically start getting plugged. I have seen a well tuned carb start to run rough, lack power and drop in miles per gallon after 10 weeks of storage with this type of gas.
When on the road by myself or with friends, if we can not find collector car gas...we just fill with what's available but I remind them to not store the car with ethanol in the tank. JMO: Never leave ethanol gas in your tank over winter!

My original post was abbreviated as a customer walked into my shop as I was entering it...I could have done a better job explaining. Sorry about that!
Good Day!

[Terry,NJ]

Hey Guys, I have a Stihl chain saw that's been giving me a hard time lately. It starts when it's cold, but not hot. Any suggestions? I've had it to the shop three times and it won't hold a repair. It's good when it comes home but it starts acting up soon afterward. My neighbor has a Echo and I was looking at Husquarna. The Stihl runs great when it starts, but I have a real problem with it when it's hot. Is it the gas?
Terry

[Tom Wesenberg]

If you have ever had the crap gas in a small engine, then the carb probably needs new rubber parts. Many chainsaws, generators, etc. have diaphram parts in the carb to act as a float or fuel pump and the crap gas will do a number on them. As Dave mentioned, it also really plugs up the small holes in the jets.