Volvo P1800 SU Carburetors Air Intake Measurement / Calibration

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I bought this from ebay few weeks ago. US$39.95 with free shipping within the USA.

Universal Carburetor Synchronizer For VW Weber, Stromberg, Solex Carbs.

I was having trouble adjusting the air intake of my SU Carburetors. I did a mistake previously by adjusting only the right carb, thought I did it right by reducing the idling RPM to a lower value. Only then I realized that there is a same screw on the left carburetor for adjustment as well. No wonder my car was always spitting petrol on the left carb when I off the engine.

After adjusting both left and right screws, I was getting pretty close to the balance left and right air intake of the carburetors, although I wasn’t very sure or confident if I was correct or wrong, without a proper air intake measurement gauge.

The Universal Carburetor Synchronizer has finally arrived last Sat. I was pretty excited and went home immediately after work. Took a quick lunch and start with my car check right after that.

Removing the two air filters was easy. The rubber cover on the front of the Synchronizer fit perfectly into the air intake hole of the carburetor, so there is no air leaks and I am sure that the measurement it takes is the air that went through it.

My previous by instinct and guessing adjustment was pretty close but not exactly perfect for the left and right carburetors. Left side was a bit under. I adjusted both side to have both readings of air intake to be around 20kg/h. Doesn’t matter what that means, as long as both are showing the same 20 figures.

I test drove the car after the calibration. In the first few kms, the car exhaust was exploding gas, I think is because of “Rich Air/Fuel Ratio Causes An Incomplete Combustion” from the previous settings. After few kilometers, the car ran fine.

By the way, before I test drove the car, I pour in my few weeks ago bought “Marvel Mystery Oil”. According to the instructions, I should pour in around 1/4 oz to every 10 gallons (37.85 litres) mixture. My full tank is around 41 litres, and since I have driven the car a few days, so I guess 1/4 oz should be OK. I poured in slightly more though.

I then poured in the rest (around 12 oz) into the engine. By right I should replace 20% of the engine oil with this MMO, that’s around 27 oz or 2 bottles of MMO, but since I only bought one bottle, so I just poured in what I have. It is recommended to change the engine oil after 500km of run with this MMO. Since my odometer is not accurate, so I will just have to be based on the refuel guestimate method. Volvo P1800 fuel consumption is 25 miles per gallon, or 9.4 litre per 100km, or 10.63km per litre. My full tank is 41 litre, so I should be able to reach around 400km per tank. So I should do the oil change after the next refueling.

Warmed up the car this morning for 5 minutes and drove it to work. The car rev so good that I really felt a big difference before the Sat work! I am not sure if it is because of the correct air intake left and right, or the Marvel Mystery Oil, or both! I drove a short 5 km and it was a really pleasant drive.