Heat Riser tube single port

[narrowfarm]

Hello,,, my single port Heat Riser tube was blocked and reading some post I was able to run a cable in my drill (in reverse) and was able to get through the Exhaust Carbon blockage with a 1/4 inch cable, took some time but it worked!!
My question is how big of a cable should I go before I put everything back together??? thanks....

[dcheek]

That should do it.

Dave
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1961 Bug
1965 Bug
1966 Sunroof Bug
1966 Westy
1976 914 2.0
1989 911 Carrera
1981 Diesel Rabbit Pick Up
1982 Diesel Vanagon
2014 Golf (last year German mfr for NA)
2019 Jetta Gli, 35th Anniversary Edition, 6 speed

[Aussiebug]

You cant get a much bigger cable through the heat riser as it's partly flattened under the carb itself to increase the heat transfer area of contact. To completely clean it out once it's been reamed with the cable, you can upend it and fill it with carb cleaner or liquid oven cleaner overnight and then blast it out with high pressure air - that will usually clean it completely.

Or you can run it as it is - so long as it's now open it will see enough heat. It might eventually block again of course.

The main reason for blockages is folks trying to run a tired engine for too long before rebuilding - you get an oily exhaust from worn piston rings etc, added to soot from a poorly maintained or worn out carb, and the result is crud being pushed into the small diameter heat riser, so it eventually clogs.
_________________
Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.vw-resource.com

[narrowfarm]

Thanks Rob for the info!! I was able to get a 5/16 cable and run it again on my drill (in reverse) and get the cable all the way though with no problem!
I am going to try also the Oven cleaner product idea over night tonight than put my car back together!!
Thanks,,, john