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Will not Idle

*New Solex Carb

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Book on How to 
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*Common 
  Motor
 Building
 Mistakes*

    10/25/08*

                            - Motor Dies or Will not Idle -

  If your VW will not idle, there are several things to check. First things first. 
Make sure the timing is set properly, the carb is clean and adjusted, the motor is in good shape (compression ck or better yet a leak down test.) Good gas and valves adjusted. dirty filter ?
Some times overlooked is the flywheel weight, to light and it's going to object to low RPM *click

  The most common problem on stock carb motors is the idle solenoid on the side of the carb. Be sure the wire is connected to the + or #15 side of the coil so it is getting the full 12 volts. On early Solex the pilot jet cutoff valve can be replaced with a fixed jet. #57 but on the later 34 Pict and Brosol H30/31 Pict carbs the idle solenoid must be in place with the inner plunger pulled back by the solenoid or some other means. Also pull the jet and make sure its not clogged with dirt. 

  Next with the key on touch the hot wire to the solenoid terminal about ten times and listen for the click every time. If you think it only clicked 8 or 9 times check it again, as it must work every time the connection is made.

  On later Dual Port carbs you will have to replace the idle solenoid if bad. On older single port carbs the solenoid can be replaced with an idle jet for a fraction of the cost. 

The idle cut off is used to stop engine "run on" when the key is turned off.

  The second most common cause of poor idle, is air leaks. Most all air leaks can easily be fixed, except the air leakage around the throttle shaft. Pull the throttle down about 1/4 to ½ open and push and pull to check for slop. When the throttle shaft is worn out we normally replace the carb. There are bushing kits available but part of the wear is on the shaft so new bushings only fix part of
the problem. 

  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. 

  Another problem you probably already checked when you set the timing is that the distributor advance and retard is working properly. With a timing light check that the advance moves smoothly as the engine speed is run up and down. The advance should stop exactly at the same spot each time the rpm is run up and down.

  Bad plugs or plug wires, cracked distributor cap, point gap, can also cause problems. (We have had some slow speed running problems with the platinum plugs ) Clogged fuel lines, gas tank strainers,( gas tank screens get clogged on old cars so we remove them completely and add an extra fuel filter at the carb.) incorrect choke operation, crushed fuel lines, gas tank vent clogged (try running with the gas cap loose ) can also cause the motor to die. Make sure the Ground Strap from Transmission to Pan is in place and connections are good, if not your trying  trying to make ground through the throttle cable. 

Cam's used in VW, Manufactures Specifications & part numbers --> *info

Question w/Answer Cleaning Intake Heat Risers of Carbon ->*Click --- Leak Down Test -> *Click --- See "Adj Valves"->*Click  --- Set Timing->*Click --- "Fuel Pump"-> *Click --- Generator Fuel Pump-> Order     Fuel Pump for Alternator Engines -> Order     

Stock Black Intake boot with cracks, about 21/2 years old & less then 100 miles driven. We recommend the Red #113 129 729R or after market Urethane Boots.

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