Carb Fire Risk?, Need advice about carbs and air filters Options

[NickFBrown]

I'm considering a '73 1.7 that some idiot put a single carb conversion on. It would be no problem a put on dual carbs instead BUT my last 914 burned when the right air filter caught fire (backfire?). It normally never backfired but this was on a hot restart after being stuck in stopped traffic on a very hot day.

Has anyone heard of this happening with dual Webers using the typical open sided air filters? I know there must be thousands of cars with this set-up. So, am I worrying for no reason.

Nick (IMG:style_emoticons/default/dry.gif)

[Superhawk996]

Let me throw one other thing your way that probably contributed.

Don’t shut off the engine stuck in traffic on hot day unless you absolutely have to.

Engine fan is constantly pulling in cooler ambient air when running (assuming all engine seals properly in place). That airflow through the carbs is cooling them.

When you shut off the engine you set up a hot soak that can boil fuel in the float bowls. Especially if you didn’t use the thermal insulators to keep head heat from transferring directly into the carbs.

At idle there is very little thermal load on the engine. Better to idle with constant airflow than shut off and heat soak as a generalization.