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Post by larry9j on Sept 13, 2012 16:46:26 GMT -5
Hey Guys, Guess what, this d**n thing is running wide open again as soon as the choke opens, no way to slow it down. Carb adjustment does not have any effect. Now, why?  ???did it run and idle last night. I guess the best thing is to deep six this d**n solex carb. I have been thinking about dual carbs, I have a set of dual weber 40 idfs on an Ed Roth trike and have had no problems I also have a dune buggy with an old Holley Bug Spray carb-also no problems. So it would seem like the Solex is the problem. |
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Post by jspbtown on Sept 13, 2012 17:03:02 GMT -5
I just can't understand how the engine is getting enough air and fuel to run wide open...especially when the lower butterfly is closed.
Even when I had a massive leak on an old single port the engine idled OK but back fired and sounded like it was running on two cylinders.
For the engine to run wildly it has to be getting an enormous amount of air and a totally unregulated amount of fuel and in a relatively good mixture.
OK...silly question....it does have the butterfly at the base of the carb?
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Post by Gary Hammond on Sept 13, 2012 17:17:17 GMT -5
Are the screws holding the butterfly valve to the throttle shaft loose, or is one screw maybe completely missing?
Is the butterfly valve bent?
Is the throttle shaft bent?
Are the throttle shaft bushings badly worn or missing?
Is the air bypass cutoff valve (solenoid) operating correctly and not sticking or damaged?
Is the air bypass screw damaged or not adjusted properly?
Does it have the "throttle positioner" that is used on some models, and if so is it adjusted properly and not defective?
When you say it runs "wide open" how mant RPMs is it actually running?
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Post by Dan MacMillan on Sept 13, 2012 17:43:25 GMT -5
Can you post some pictures
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Post by larry9j on Sept 13, 2012 19:46:10 GMT -5
OK, here goes
butterfly valve in place, not bent, and working ok
throttle shaft not bent
throttle bushings in place but could be bad
idle solenoid in place and seems to be working correctly
neither carb adjustments work at all while the engine is running away
engine is running extremely rich
carb not equipped with a throttle positioner
carb does have a second lever, like a throttle lever, with its own adjustment screw, I have no idea what this lever is or its purpose
thanks,
Larry
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Post by Gary Hammond on Sept 13, 2012 20:14:35 GMT -5
Hi Larry,  According to the book, one is the throttle lever and the other is the fast idle lever!  The fast idle lever adjustment screw should contact the cam on the choke shaft, and the throttle lever should have a stop screw for setting the idle speed when the choke is off. Opening the choke should cause the fast idle cam to move away from the fast idle lever and when fully open have a gap between the cam and adjusting screw. Is it somehow set up backwards from this? Don't even know if this is possible or not by looking at the book, and I don't have one of these to compare.  Gary Hammond,   P.S.----What is the RPM when it's "wide open"? |
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Post by skip20 on Sept 13, 2012 20:17:36 GMT -5
Spray carb cleaner on the throttle bushings( in place but could be bad )
Is speed change you have a VAC leak!!!!!!!!!!!
Get a new carb, they are CHEAP for a VW
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Post by larry9j on Sept 13, 2012 20:25:18 GMT -5
Gary,
Can you direct me to something that shows the adjustment procedure for this throttle lever with the stop screw.
I have 3 other junl 34 pict 3s and none have this lever
Thanks
Larry
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Post by Gary Hammond on Sept 13, 2012 21:58:21 GMT -5
Hi Larry, The book I have doesn't show how to adjust the linkages except for the throttle positioner system. The throttle positioner provides the same function as the "dashpot" on American cars. Causes the throttle to return closed slowly. With the engine cold and not running turn the choke thermostat housing index mark to line up with the center index mark on the carburetor. Then manually open the choke butterfly with your fingers from inside the throat of the carb while holding the throttle lever open with your other hand. The fast idle cam should now be raised to its highest position. While still holding the choke open, allow the throttle linkage to return to a closed position. There should be a small gap between the adjustment screw of the fast idle lever and the fully open cam. If there is no gap, back the screw out until there is about a .030" gap here with the choke fully open. While still holding the choke open, back off the adjusting screw of the throttle lever (the other lever) until the screw no longer contacts the carburetor body. Check to see if the throttle plate is now totally closed. If it is, you should feel it slightly sticking in the throttle bore when moving the throttle lever. Then tighten the screw back down until it just contacts the carburetor body and give it about one turn more to slightly open the butterfly. Now you can release the choke butterfly and set the cam to the closed position by opening the throttle lever and then releasing it. The adjusting screw on the fast idle lever should now be contacting the fast idle cam to hold the throttle slightly more open for a cold start. Start the engine. As the choke warms up, it should open and the engine speed up a little. Blip the throttle to allow the fast idle cam to rise. The fast idle adjusting screw is only used to adjust the fast idle on a cold engine while the choke is on. When the choke is off, the throttle arm screw, the idle mixture screw, and the idle air bypass screw are used to adjust the idle. Without having your carburetor in front of me and not having clear instructions myself, this is as good as I can do. This is just a general procedure for most carbs I'm familiar with. If this doesn't work, try Samba.com. Gary Hammond, |
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Post by larry9j on Sept 15, 2012 17:37:31 GMT -5
Hey guys,
Cross your fingers, I rebuilt the carb today (2nd time) and the engine seems to run good, idles at about 850 rpm and dwell angle about 46 degrees. Starts right up and idles ok, you can speed the engine up and it sounds really good, let off the throttle and it drops back to 850 rpm.
I have no idea why it seems ok after the 2nd carb rebuild, the only thing I did different was use a different rebuild kit.
One problem poked its ugly head, the throttle shaft bushings now seem to be leaking as you can see it leak after the engine is shut off.
There is a big vw show in Cincinnati on 9/30 I'm going to go and see if I can find a set of dual carbs or maybe a new solex and put this old carb to RIP.
Thanks for all your help everyone.
Larry
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Post by Wyn on Sept 16, 2012 10:14:27 GMT -5
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Post by Dan MacMillan on Sept 26, 2013 20:03:10 GMT -5
Vw vac lines are always sized. Small port on drivers side goes to small port on dist [adv]. big port on back of carb to big dist port [retard, if you have a dual vac dist] all others get plugged. |
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The fast idle lever adjustment screw should contact the cam on the choke shaft, and the throttle lever should have a stop screw for setting the idle speed when the choke is off.
