1800vw

In Order to adjust the carb properly you must have the Valves adjusted and the timing set properly. Note: You can not set the timing by ear.
If the timing is set at idle where it runs the smoothest you will destroy your Motor.

Check that all the hoses are in place and the base gasket is sealing properly.

Install your air cleaner and proceed.

..The big difference in the newer carbs is that the Idle speed is set by the big brass or aluminum screw on the left side of the carb. #36 on Solex parts page

But first lets set the throttle plate.

Back off the throttle screw located up at the top of the throttle arm. #34 on Solex parts page

Now with the choke held in the full open position place a piece of notebook paper (.003) between the lowest step of the choke fast idle cam and the adjusting screw.

Then slowly turn the screw in until you feel the drag on the paper. Remove the paper and turn the screw in precisely ½ turn.

Next set the volume of gas available at idle speeds.

This is the small screw located just above the Idle Cut off solenoid (where the elect. wire hooks on the left side) #39 on Solex parts page

Turn the small screw all the way in until it "gently" bottoms out. Then back it out 2 ½ turns.

Now start the engine and let it warm up.

Set the Idle speed by adjusting the Large idle bypass screw which is just above the small screw you just backed out 2 ½ turns. #39 on Solex parts page

Note: The idle speed is set with the volume of air going by the Bypass screw and not the throttle arm screw as on older carbs. #36 on Solex parts page

The idle speed should end up about 650/700 rpm.

If you don't have a tack set it by ear but remember it's far better to have the idle speed too fast then too slow.

Now that the motor is warmed up and the choke is in the full OFF position slow the Idle speed so it just keeps running.

Next go back to the gas volume screw (the small one in the recessed hole) and adjust it in and out until the fastest (smoothest running) idle speed is found. #39 on Solex parts page

Now that we found the sweet spot, back the screw out approximately 1/8* to1/4* turn.
*This is normally required in order to get a smooth transition from idle to low rpm range.

We want it just a little on the rich side. Now go back to the large Air Volume Bypass screw and reset the Idle speed but remember fast idle is better then too slow.

Too slow an idle speed can cause the motor to overheat.

The VW motor produces the most heat under Full Load and Slow Idle.

Set the choke so it just barely closes. It's better to set it to loose at first as you can always go back and tighten it up depending on your climate and driving style.

Same for the accelerator pump. If it stumbles when you put your foot in it, then you will want to increase the stroke.

Before changing any other fixed jets or modifying mid-range or top-end jetting you will need to take plug readings to see if you are rich or lean.

For Modified Motors & Performance Tuning *Click <-here for "Solex Tuning"

If the motor is in decent shape your carb is now adjusted.

Note: If you do normal High-way driving, Back and forth to work and not a hot rodder, there is nothing wrong with replacing the old DP carb with the less expensive SP Carb. *ck <- New Carb

Note: If your car seem cold natured, you might have clogged Heat Risers.
Question w/Answer Cleaning In Heat Risers of Carbon ->*Click

BUT if the valves leak and the compression is to low or the timing advance doesn't work or the throttle shaft bearings are loose no amount of adjusting is going to make it run right.

Check for air leaks with some starter fluid. With a can of starter fluid in one hand and a fire extinguisher in the other, start your motor and set it to idle as slow as possible. Spray the starter fluid around the base of the carburetor, throttle shaft, dual port boots, vacuum ports etc. If there is an air leak the idle speed will increase slightly. The hardest place to check is where the dual port end castings bolt to the head. The air from the fan will blow the starter fluid away before a leak can be detected. To check for dual port end casting air leaks, you must start with a cold motor. First remove the fan belt, then start the motor and spray starter fluid around both end castings where they bolt to
the head, then quickly shut the motor off before it over heats.

On carburetor rebuilds or when replacing your carb. Always check the intake manifold to make sure the surface is flat. We find about 50% of used carbs need the base flattened. After removing the mounting studs, a sheet of emery paper on a flat surface can be used to true the carburetor base
flange.

One last thing you might want to remember and that's what we call a $1.98 tune up.
Remove the Air Cleaner & Start the motor.
Rev it up good and slap your hand over the top of the carb.
This creates one heck of a vacuum through out the carb. It either pulls the dirt out of the jets or sticks it in real tight.

New DP Carb->*ck --- New SP Carb->*ck --- SP to DP Adapter->*ck ---Rebuild Kit->*ck --- Won't Idle->*Click

To see what jetting the stock Solex Carb comes out with.->*Click --- Fuel Pump -> Order --- Main Jets-> order

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Victor Comp. Products Inc. **--Vic's--** Phone 816-650-3535 • 230 S Hudson St., Buckner, Missouri, 64016, US

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