Gas Saving Tips On The Solex 4a1

[jpp]

I Have An W116 280s, And Iam From South Africa, We Have No Cold Winters, Never Below 5 Degrees Celsuis And Hot Summers.the Factory Carb On This Car Is The Solex 4a1, Basically 2 Mediocre Dual Barrel Carbs Combined Into Major 4 Barrel.
If You Dont Have Sub Zero Cold Weather To Contend With, Do The Following Easy Modification To Improve Low End Power And Gas Milage

[jpp]

1. Remove The Choke Butterflies Including The Mounting Rod Over The Primary Venturis. Bypass The Choke Water Manifold With A Connecting Copper Tube To Join The Hot Water Hoses.
2. Remove Hot Water Hoses From The Y Manifold Of The Termal Piston Assembly At The Carb Body. The Termal Piston, When Cold Is Held By A Small Strong Spring. At This Position, It Permits More Fuel Into The Venturis. If This Bugger Stics In The Retracted Position Because Of Water Crud Insulating The Piston You End Up With Chronis Over Rich Running.
3. Remove The Screws Of The Spring Body From The Water Body And Take Out The Spring. Insert A Spacer Or Series Af Washers Between 4-5mm In Total Behind The Piston, So That The Piston Is In The Extended Position. Refit Piston Body To Water Body.the Y Branch Manifold Is Now Redundent
4. You Now Have A Card Permanently On Operating Tempreture Mixture
5. The Method Of Starting Is Simple, Just Pump The Gas Pedal 3 Times, The Engine Will Fire Immediatly
6. I Have Much More Low End Power Due To Less Induction Drag From The Choke Flaps, And My Gas Milage Has Inproved By 25%!!!!

[PILOT MAN]

Has Anyone Tried What This Guy Suggested? Does It Work/will It Word, What Does The Experts Say?

I Have A 4a1 And The Economy Is Bad, Real Bad The Car Is 280 W123, I Get About 6.5km Per Litre Highway Driving At 120km/h

Exhaust Is Burning Light Grey As I Am Using Leaded Gas

[Rob Pruijt]

The Solex 4A1 is one of the best carburettors ever made (one of the most complicated to!). I would not recommend modifying it to get better fuel economy. Since it is at least 20 years old it may be worn, dirty, or maladjusted. Unlike the injection version, the carb version has only very limited fuel filtering. On the M110 it is very easy to remove and the carb is easy to disassemble. Clean everything, especially the air ducts and try to adjust it. Without testing equipment this may be hard, but there is a lot of information on this carb. With some trial an error it can be done. I used a transparent spark plug to adjust the mixture, this worked fine.
On both my W115 280 and my W126 280S I got 1liter/10km at 120Km/h, fully loaded (towing a caravan at 150km/h decreased the fuel economy dramatically).

[Dlespera]

Hello folks,

Rob is correct. I have said carb and just clean/adjust it carefully. I used to get 10-12 l/100km out of it but get more like 13-14 now

The reason is that I fitted my car with some Lorinser rims and 225/50x16 Contis. The extra drag has really cost me fuel economy but cornering and braking is SO much better that I don't care. The car is much safer !

Denis
Lion sur Mer
France

[JeffreyNMemphis]

Bonjour Denis!

J'aime la France!

Je suis desolee' pour non-voiture salut. Just parle et regard mon amis Francaise.

Viva la France!

[JeffreyNMemphis]

Wow, Denis...

Did you see the date of this post? It is two years old...

But I am still happy to see a Frenchman writing on the forum.

All the best,

Jeffrey

[wbain5280]

Some people have replaced that carb with a Rochester or Holley carb.

Quadrjet too:

Q-Jet on m110

[wolf_walker]

I finally got up to 16mpg combined on my 280, with a 4a1 from a 250, which is slightly less U shaped than the original. I'm sure they were a fine carb, but they way they warp is just silly.

[Dlespera]

Hi folks,

Thanks JeffreyNMemphis !

My point is that the infamous warpage problem on this carb is not usually a problem here as people who touch them seem to know them. They ARE complicated but can be made to work OK if you follow factory instructions.

Its too bad that they were used on the Rolls coupe as this drove their prices off the planet's surface (over 2200€ last time I looked).

As for Holleys, we dont have them here
It is cheaper to convert the cars to K-jet !

Denis

Lion sur Mer
Normandy, France

News from the coast: spring is coming and Obama is visiting us June 6th