Proper Fuel Mixture - Exhaust residue.

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Chris Stavros
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Proper Fuel Mixture - Exhaust residue.

#1 Post by Chris Stavros »

Before I start messing with the obvious; jetting, mixer adjustment, float bowl level, etc., I'm open to hearing from the experts as to what they've concluded solves the excessive fuel smell and richness residue left on the bumper guards. NOTE: I cleaned this bumper guard 600 miles ago.
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Last edited by Chris Stavros on Fri Aug 19, 2022 8:19 am, edited 1 time in total.

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Jim Liberty
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Re: Proper Fuel Mixture - Exhaust residue.

#2 Post by Jim Liberty »

DSC_0021.JPG
Put on an extension tip. All of our vendors have them. ................Jim.
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Wes Bender
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Re: Proper Fuel Mixture - Exhaust residue.

#3 Post by Wes Bender »

That's normal. I wouldn't start messing with the carburetors. Put the tips on per Jim's suggestion. The bumper guards will stay clean and only the edge of each tip will need cleaning.
Some days it's just not worth chewing through the restraints.....

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Mike Wilson
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Re: Proper Fuel Mixture - Exhaust residue.

#4 Post by Mike Wilson »

It's most likely soot plus the condensation that builds up in the muffler and spits out.

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Jon Schmid
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Re: Proper Fuel Mixture - Exhaust residue.

#5 Post by Jon Schmid »

+3 on the above suggestions. The "extenders" are not a factory stock item (they should have been) but cleaning the tips instead of the bumper guards is well worth the money. Plus, you won't get the heat discoloration on the guards. After having my dad's Roadster in the family for 62 years, half with and half without the tips, I speak from experience. Get the tips!! 8)

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C J Murray
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Re: Proper Fuel Mixture - Exhaust residue.

#6 Post by C J Murray »

Yes that soot is normal.

Asking about "excessive fuel smell" is a different question. Compared to modern cars all 356s smell rich. How rich is too rich? It's hard to tell by looking at a tailpipe or by smell. If the car drives well and has reasonable fuel consumption then ignore the soot and the smell. If the fuel consumption is excessive then you investigate further.
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Tom Wavrin
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Proper Fuel Mixture - Exhaust residue.

#7 Post by Tom Wavrin »

This product used on the exhaust guards will keep them clean and bright. Quick and easy to use. Heat resistant acrylic coating. I prefer the guards w/o use of the tips.
https://www.autogeek.net/klasalpolsea2.html
I have the kit that includes the sealant. I ‘wax’ the car every 2 or 3 years but clean the guards often. Takes just a couple of minutes.
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Al Zim
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Re: Proper Fuel Mixture - Exhaust residue.

#8 Post by Al Zim »

Chris: the answer is fuel injection! You are welcome to call Aaron regarding this solution. Thank you zim
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Mike Wilson
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Re: Proper Fuel Mixture - Exhaust residue.

#9 Post by Mike Wilson »

Hey, Al. Have you done an article about the fuel injection system? If not, I think it would be well-received. If I recall, the system requires 12V, right?

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Martin Benade
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Re: Proper Fuel Mixture - Exhaust residue.

#10 Post by Martin Benade »

And I bet the bumper guards will still get darkened. But I also would love to know more about the system.
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Re: Proper Fuel Mixture - Exhaust residue.

#11 Post by Brian R Adams »

Tom Wavrin wrote: Mon Aug 15, 2022 11:32 am This product used on the exhaust guards will keep them clean and bright. Quick and easy to use. Heat resistant acrylic coating. I prefer the guards w/o use of the tips.
https://www.autogeek.net/klasalpolsea2.html
I have the kit that includes the sealant. I ‘wax’ the car every 2 or 3 years but clean the guards often. Takes just a couple of minutes.
Interesting tidbit in the product marketing:
NEVER USE DISH DETERGENT for washing your car. Use a capful of this polish instead. Although you will not have a foamy cleaning solution, dirt will be lifted from your vehicle’s surface.
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Tom Wavrin
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Proper Fuel Mixture - Exhaust residue.

#12 Post by Tom Wavrin »

570DB9E0-E68F-48B5-A627-E21ECB3EE69B.jpeg
Guard after 12 years of use.

Brian, I noticed that too. There’s a bit of chemistry involved in the making of detergents. Dish soaps can be a little harsh for use on waxed car surfaces. Same if used as a hair shampoo. I use a car wash soap that has surface active agents that are designed to remove that type of dirt.
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Chris Stavros
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Re: Proper Fuel Mixture - Exhaust residue.

#13 Post by Chris Stavros »

Thank you all for your input. I've spoken to Jim at Carburetor Rescue and he also gave me a little insight on "factory" carburetor settings, versus his modified settings using today's fuel (another topic). He suggested I lower my float bowl levels to 20mm (currently set at 18mm), and lower my accelerator injection volume to .2cc (per two strokes)....(currently at .25cc). I'm hoping to tackle this over the weekend, but honey-do's may alter my plans :-). I'll keep you all informed.

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Re: Proper Fuel Mixture - Exhaust residue.

#14 Post by Brian R Adams »

Chris Stavros wrote: Fri Aug 19, 2022 8:26 am Thank you all for your input. I've spoken to Jim at Carburetor Rescue and he also gave me a little insight on "factory" carburetor settings, versus his modified settings using today's fuel (another topic). He suggested I lower my float bowl levels to 20mm (currently set at 18mm), and lower my accelerator injection volume to .2cc (per two strokes)....(currently at .25cc).
I probably missed it, but are these Zeniths?
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Re: Proper Fuel Mixture - Exhaust residue.

#15 Post by Wes Bender »

Don't expect miracles Chris. Carb Rescue is giving you good advice on tuning, but as long as you are burning a fuel that generates even a tiny bit of soot & heat, you'll continue to see some discoloration. If I remember correctly, Harry Pellow suggested pointing the 90 degree tubes coming out of the muffler down to stop the discoloration.
Some days it's just not worth chewing through the restraints.....

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