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Tomthebeetleman

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Reply with quote  #1 
So I have a freshly rebuilt 1600 vw air cooled engine and it won't idle. I have done a lot of work on the engine. For example, it has a new crank, all new gears, new case, new cam followers, new heads, new post one and cylynders, new distributor, new carburetor, etc. Did a leak down test and it has virtually no leak. Did I fuel pressure test and it was well within specs. I ran the engine for a 20 min and cylinders 1 and 3 ran a lot cooler than the rest (I checked the temp at the exhaust and 1 and 3 were about 100°F less than 2 and 4). I checked the spark and they all looked good. At this point I'm pretty stumped. I have done a lot of tests so if anyone has any idea about what it could be I am open to anything.
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bob

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Reply with quote  #2 
Did you check your electric cutoff switch on the side of the carburetor??? Usually if its bad you can unscrew the switch, cut off the plunger and re install, I went as far as breaking off the electromagnet and welding the plunger hole shut, I also pulled all the brass tubes out of the carburetor and filled the holes with epoxy.

Bob 
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Tomthebeetleman

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Reply with quote  #3 
I just bought the carbuerator probably a month ago. And when the ignition turns on you can here a click on the electronic cutoff switch.
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bob

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Reply with quote  #4 
You can back out both the adjustment screws a half a turn on the side of the carburetor and see if that helps.

Bob
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Tomthebeetleman

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Reply with quote  #5 
I tried to adjust the screws. All over the place and still no real significant changes. I did check for a vacuum leak because I figure that it might not be adjusting because of that but I didn't find any leak. I used the ether method. I have a feeling that my cam lobes might be flattened out but I'm not completely sure yet. The can is one of the only things I haven't changed out on this motor
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bob

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Reply with quote  #6 
Make sure you have a thick gasket under your carb or two thin ones, do a valve job with a 6mm feeler gauge and then have someone roll your engine, coil off, while you are looking underneath at the valves, if the lobes are shot there will be little if any movement and check to see if your plugs are tight.

Bob
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Tomthebeetleman

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Reply with quote  #7 
Okay. I will give it a try!
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bob

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Reply with quote  #8 
I just had a horrible thought that the gap of the piston rings were not offset from each other, causing blow by, I have actually seen this happen on larger engines, the rings gaps where lined up in a row and installed in the block, there was no compression and the engine had to be dis assembled, once you pull the valve covers off, roll the engine, coil off and check your valves for movement, then you can pull the plugs and check compression with a gauge, little compression means little vacuum equals no idle.

Bob 
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Tomthebeetleman

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Reply with quote  #9 
So I ended up tearing the engine back down and replaced the cam that I though was good. Turned out it wasn't. Thd engine now runs great! Thanks for all the input!
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