Tracking down a backfire problem - SOLVED - Thank you all!

[scottyrocks]

I've been through 3 new condensers in the last few months. I solved that one by subbing in a printed circuit board capacitor that should last a lifetime.

Before I did anything else today, I added a second gasket under the top of the carb cover (pardon my terminology). The gaskets in the rebuild kit seemed a little thin, especially compared to the one that was there before the rebuild.

The float bowl level seemed a little low, so I added the second gasket to bring the float needle, and hence the float level, up a bit.

As soon as I started the car I could tell it was idling more smoothly.

I drove it around the neighborhood to warm it up a bit, and then got on the parkway.

All sense of hesitation is gone. It got up to an indicated 70 mph more quickly than it did before, and it is now very smooth. I held it there for a while and then took my foot off the gas. No popping, no backfiring, no explosions. Rinse and repeat. No issues.

So another thing to check, especially if you've had it apart, is the float level. Too low and it can mimic the backfiring caused by intake and exhaust leaks, as well as timing and points being wrong.

I may have finally gotten everything all straightened out.

The car is running like a champ now.
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“If you care for a thing long enough, it takes on a life of its own, doesn't it? Mending old things, preserving them, looking after them – on some level there's no rational grounds for it.”
– D. Tartt, 'The Goldfinch'

[bluebus86]

excellent!

Details like fuel pressure, bowl level, accelerator pump volume are detailed in the Bentley Manual, and they should always be checked and adjusted as needed when ever a corresponding new part is installed.

I have had bowl level change a lot with a new valve, and a huge change in accelerator pump volume with a new diaphragm. And all sorts of different gasket thicknesses. Parts are made by many firms, in many nations, and some have vastly different tolerances, and dimensions, than others. Just a little change in lifter length on the accelerator diaphragm, and the volume per stroke went out of specification, thus needing adjustment on the linkage rod.



Bug On!
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Help Prevent VW Engine Fires, see this link.....Engine safety wire information

Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022