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Old 08-04-2015, 04:42 AM   #1
Sly
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Default air - fuel mixture ?

Hi,

my Tudor is running with a Tilloston X carb.

two problems are excisting:

- to rich mixture followed by sooted spark plugs and bad and worse running.
the idle mixture srew is turned in fully and still an measured mixture of 6.9 % CO2 in idling mode. 4.1 % CO2 on half gas. 2.5 % should be the right number.

- fuel is running out of the airintake part of the carb when the engine is turned off.

The was overhauled last year, maybe I did something wrong.

Has somebody an idea?

BR STefan
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Old 08-04-2015, 05:13 AM   #2
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Default Re: air - fuel mixture ?

I would suspect either the float is punctured, or the petrol valve operated by it is not sealing. If there is petrol inside the float, your can find the hole by putting it in a glass and looking for the bubbles.
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Old 08-04-2015, 05:35 AM   #3
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Default Re: air - fuel mixture ?

has this carb flooded since the rebuild? or later on after use? maybe a little crap got into the float valve,,
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Old 08-04-2015, 05:38 AM   #4
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Default Re: air - fuel mixture ?

My first thought is the same as ppower, Heat the water to cause the air to expand a little and force it out of the float.
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Old 08-04-2015, 06:33 AM   #5
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Default Re: air - fuel mixture ?

The idle screw is screwed in fully???? It should be rich. Open it up and let some air in.
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Old 08-04-2015, 06:40 AM   #6
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Default Re: air - fuel mixture ?

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When I rebuilt mine, I made sure to blow air out in both directions at every point. The air mixture was set at 3/4 turn and it runs fine.
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Old 08-04-2015, 08:55 AM   #7
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Default Re: air - fuel mixture ?

...sorry the other way around, your are right..
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Old 08-04-2015, 10:19 AM   #8
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Default Re: air - fuel mixture ?

Just went through a similar issue with my '31, (plugs sooting up, runs like crap, smoking)
A quick and easy little test...take off the air cleaner, see how she runs,
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Old 08-04-2015, 12:18 PM   #9
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Default Re: air - fuel mixture ?

Quote:
Originally Posted by Sly View Post
...sorry the other way around, your are right..



What does that mean ?
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Old 08-04-2015, 12:25 PM   #10
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Default Re: air - fuel mixture ?

Quote:
Originally Posted by burner31 View Post
Just went through a similar issue with my '31, (plugs sooting up, runs like crap, smoking)
A quick and easy little test...take off the air cleaner, see how she runs,
^^^^^^^
What he said!!!

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Old 08-04-2015, 02:13 PM   #11
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Default Re: air - fuel mixture ?

Screwing in makes the idle mixture lean.
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Old 08-05-2015, 12:12 AM   #12
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Default Re: air - fuel mixture ?

It seems it isn`t easy the thing with the mixture screw. Now I am totally confused - Henry said screw in makes it lean, Jackson said the opposit??? Does anybody have a detailed manual or link for the Tilloston X?
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Old 08-05-2015, 12:58 AM   #13
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Default Re: air - fuel mixture ?

Screwing in closes the opening, screw out opens the opening, it's a needle valve.

Did you take the air filter off?
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Old 08-05-2015, 09:04 AM   #14
Tom Wesenberg
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Default Re: air - fuel mixture ?

The screw on the original Zenith carb controls the air while the norm for most all other cars is the low speed mixture screw controls the gas, so this makes it confusing for those not aware of the difference.
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Old 08-06-2015, 07:31 AM   #15
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Default Re: air - fuel mixture ?

...no I didn`t, why? Do you think the filter does not get enough air?
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Old 08-06-2015, 07:33 AM   #16
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Default Re: air - fuel mixture ?

Tom,

do you know about the Tilloston x?

Which direction (mixture screw) does allow more air?
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Old 08-06-2015, 08:05 AM   #17
Tom Wesenberg
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Default Re: air - fuel mixture ?

Quote:
Originally Posted by Sly View Post
Tom,

do you know about the Tilloston x?

Which direction (mixture screw) does allow more air?
No experience with the Tillotson, as I've only run the original Zenith carbs. I had a chance to buy a NOS Tillotson still in the box for $10 about 7 years ago, and I should have bought it just to try it.
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Old 08-06-2015, 09:34 AM   #18
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Default Re: air - fuel mixture ?

Sly: I run a Tilly, damn good carb, the mixture screw is a needle valve, pull it out and look at it, run it back in all the way then open it up 1/2 to a full turn, you'll find the sweet spot...take that damn paper air filter off and see what happens.

Tom: For $10 you should have picked that up, and if you did not use it on your car...well...you know... there's always...hint, hint...Christmas...is only...you know...four months away...and then...you know...there's always...you know...hint, hint...my Birthday.
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Old 08-06-2015, 01:01 PM   #19
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Default Re: air - fuel mixture ?

hi, I do not run a paper filter,just a wire netting one.
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Old 08-06-2015, 02:11 PM   #20
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Default Re: air - fuel mixture ?

Is the float level set correctly? Too high a float will cause rich mixture and gas running out the inlet. Idle mixture controls the air. Are you turning the gas shutoff valve off and running until the gas is used up in the fuel bowl before you turn the motor off? A very good idea there.

https://sites.google.com/site/mrtexa...ly-carburetors
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