Mixture Screw?

65_Stang_170

Well-known member
Hey all! First time posting... Taking apart my carb (Autolite 1100) to rebuild, and came across this idle mixture screw. It doesn't look right to me as most have a point at the end and are much smaller. Does this thing look right or do I need to get a new one? Thanks for your help!

-Shawn
 

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Howdy Shawn:

And welcome to The Forum.

That Idle mixture screw is definitely NOT right. I'm guessing from your signature that this carb is from a 170 engine. So, try to find a correct replacement mixture screw for an Autolite 1100 from a 170 engine.

And it would be a good idea to fill us in on your project. Again, Welcome.

Adios, David
 
So, I just got my rebuild kit, and looking at the exploded view (attached), it looks like the right one... I have a 65 mustang coupe with a 170 and a 3.03 manual transmission. It didn't seem like it was running that well, and there was some fuel leaking from the carb, so I decided to rebuild it. I borrowed a timing light and got the initial timing back toward factory specs (it was wayyyyyyy off). Hooked up a vacuum gauge and adjusted the mixture screw and got it in a good spot. I don't have a tach, so I couldn't really get the idle speed zeroed in. Anyway, i removed the carb and took it apart and found that mixture screw and couldn't find one like it when I tried googling it.
 

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65_Stang_170":4xc2cxak said:
So, I just got my rebuild kit, and looking at the exploded view (attached), it looks like the right one... I have a 65 mustang coupe with a 170 and a 3.03 manual transmission. It didn't seem like it was running that well, and there was some fuel leaking from the carb, so I decided to rebuild it. I borrowed a timing light and got the initial timing back toward factory specs (it was wayyyyyyy off). Hooked up a vacuum gauge and adjusted the mixture screw and got it in a good spot. I don't have a tach, so I couldn't really get the idle speed zeroed in. Anyway, i removed the carb and took it apart and found that mixture screw and couldn't find one like it when I tried googling it.

:unsure: Good plan on doing the carb rebuild! You stated the timing was way off from factory specs, what was it? With the old LOD using the stock timing specs dosent work the best with today's fuels what did you set your base timing to now? With these LOD systems I start with at least 10 or 12 degrees and tune from there to see what the engine likes. To get your tune more accurate you will need the use of a tach / dwel meter especially if your Distribitor is still using the stock type points.

A good tune up follows this order of work
1. Set the plug gap .034.
2. Set the points basic setting to .025 after its runing set the Dwell Angel to factory spec of 38 degrees.
3. Now you need to set the timing at 10 to 12 degrees base timing this may need to be changed to as much as 16 degrees BTDC all depending on how your engine responds with any hint of pinging under more than a slight load (going up a small grade) back off timing a little at a time until it stops.
4. Set the Idle mixture to its Lean Best Idle.
5. Set the curb idle speed to 500 RPM.
6.Repeat 4. & 5. To see if it improves anymore.
You might also test your coils output with the volt / ohm meter as well as the plug wires and cap for their resistance readings are in spec. Good luck in your tuning (y) :nod:
 
bubba22349":2s8wkkss said:
:unsure: Good plan on doing the carb rebuild! You stated the timing was way off from factory specs, what was it? With the old LOD using the stock timing specs dosent work the best with today's fuels what did you set your base timing to now? With these LOD systems I start with at least 10 or 12 degrees and tune from there to see what the engine likes. To get your tune more accurate you will need the use of a tach / dwel meter especially if your Distribitor is still using the stock type points.

A good tune up follows this order of work
1. Set the plug gap .034.
2. Set the points basic setting to .025 after its runing set the Dwell Angel to factory spec of 38 degrees.
3. Now you need to set the timing at 10 to 12 degrees base timing this may need to be changed to as much as 16 degrees BTDC all depending on how your engine responds with any hint of pinging under more than a slight load (going up a small grade) back off timing a little at a time until it stops.
4. Set the Idle mixture to its Lean Best Idle.
5. Set the curb idle speed to 500 RPM.
6.Repeat 4. & 5. To see if it improves anymore.
You might also test your coils output with the volt / ohm meter as well as the plug wires and cap for their resistance readings are in spec. Good luck in your tuning (y) :nod:

Thanks for the tips! The timing mark was almost on the other side of the harmonic balancer... it took quite a bit of turning to get it back to the scale/meter whatever you call the thing on the timing cover. It seemed to like that much better. I put it between around 6 (factory for manual transmission). Once I get the carb back on, I'll repeat the process.
 
65_Stang_170":2slir2s1 said:
bubba22349":2slir2s1 said:
:unsure: Good plan on doing the carb rebuild! You stated the timing was way off from factory specs, what was it? With the old LOD using the stock timing specs dosent work the best with today's fuels what did you set your base timing to now? With these LOD systems I start with at least 10 or 12 degrees and tune from there to see what the engine likes. To get your tune more accurate you will need the use of a tach / dwel meter especially if your Distribitor is still using the stock type points.

A good tune up follows this order of work
1. Set the plug gap .034.
2. Set the points basic setting to .025 after its runing set the Dwell Angel to factory spec of 38 degrees.
3. Now you need to set the timing at 10 to 12 degrees base timing this may need to be changed to as much as 16 degrees BTDC all depending on how your engine responds with any hint of pinging under more than a slight load (going up a small grade) back off timing a little at a time until it stops.
4. Set the Idle mixture to its Lean Best Idle.
5. Set the curb idle speed to 500 RPM.
6.Repeat 4. & 5. To see if it improves anymore.
You might also test your coils output with the volt / ohm meter as well as the plug wires and cap for their resistance readings are in spec. Good luck in your tuning (y) :nod:

Thanks for the tips! The timing mark was almost on the other side of the harmonic balancer... it took quite a bit of turning to get it back to the scale/meter whatever you call the thing on the timing cover. It seemed to like that much better. I put it between around 6 (factory for manual transmission). Once I get the carb back on, I'll repeat the process.

:shock: :wow: :banghead: with the Dampner having slipped that much there isn't any chance of knowing with any accuracy what your timing is set too. Might be a good time to hunt for one in better condistion or get a rebuilt Dampner. Good luck :nod:
 
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