I got this query from one of our club members, re. his Superbug with a Weber DFEV. Any suggestions?

"A few months ago I imported a genuine 32/36 DFEV Weber carburettor from the USA together with a Redline conversion kit number K1410.

Recently I had it fitted to my 1973 Super bug as I was never happy with the original carburettor as sometimes it was hard to start and seemed to lack adequate power.

I had looked up comments on the internet from people who had already fitted Webers and they listed only two complaints:

a/. They were hard to adjust because the adjustment screws were placed awkwardly when fitted to the 1600 motor.

b/. In wet weather, rain could come in through the air vent louvres on the engine bay lid and penentrate the air filter.

With regard to the first complaint; my mechanic used specialized tools and had no trouble adjusting the carburettor.

The car has been standing in some pretty heavy rail and, to date, although rain had got onto the engine and air cleaner cover, no problems have been experienced.

Since fitting the Weber, the engine has started on the first crank, and I have found that the performance of the motor (particularly the torque) has been outstanding.

However, I have encountered one drawback for which you, or your readers, may have a cure. I would certainly appreciate their comments.

When I switch off the ignition, the motor continues to "run on" (particularly if it's hot) and I have found that the only way to stop this, is to throw the car into second gear and let the clutch in. The mechanic has done a "de-coke" of the engine and has adjusted the idle speed to the slowest possible idle, but to no avail. The problem still persists. I understand that VW were well aware of this and fitted an electronic fuel cut-off valve into the original carburettor. The Weber has no such valve."

is it tuned correctly? Just wondering if it is running a bit lean. Also is it running on premium?

My van has a Weber DF(or is it G)EV on it. Haven't had any real running on issues. It takes a second or two to die but I consider that acceptable.

I remember some time in the dark ancient history of my van it did have a dieseling problem. My compression ratio was way too high for regular unleaded. Cracked a head in no time because I failed to address the underlying issues,.

To me it sounds like a lean running issue.

I had this problem on my 76 kombi and solved it by adjusting the valves. How this worked I don't know but the adjustment fixed it!

PS. The engine would run backwards when it ran on!

Simple motors which can do mysterious things, including eluding diagnosis of problems. Speaking of which, thought I'd spend a little bit of the aussie day pubic holiday working on the van.

Yes it is most likely a bit lean
and the residual heat continues to keep the combustion process going,
even though there is no spark in there.

This can be worse with hot weather.

Here are some things to try:

Correct the jetting.(use a probe in the exhaust to confirm and adjust mixtures).
Reduce total spark advance.(either by adjusting the timing or re-curve the distributor),
one step colder spark plug.