Ongoing Carburetor testing.

Builders,

The previous story covered updating the aluminum pushrod tube installation in my own personal Corvair engine. This was half of a particulars day of testing. The other half was to run the particular NAS-3A Stromberg carb pictured below. It has a different set of jetting in it, and we are working to fine tune it, and add that set of data to our carb knowledge.

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Strombergs are a traditional carb, not only for Corvairs, but for US light aircraft in general. The have a long track record of very good service. The particular one has a variation on what we have previously done before, and thus a test run was in order.

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Above, freshly overhauled Stromberg, running on my 3,000cc Corvair. The Fuel filter is an Earl’s unit available from Summit Racing, it has an accessible element and -6 AM male fittings on each end. My test stand has had one for years, and I also have one on my plane. Be very careful not to install it in a plane in a position where it could trap water.

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The photo doesn’t quite capture it, but the jetting or setting was on the rich side. Under some circumstances, it was producing visible black smoke. Look at how dark the tailpipe is. Keep in mind this is running on pure unleaded car fuel. ┬áThe Exhaust piped on my test stand have had 18mm threaded ports in them for the last 10-12 years, and I have used them with a wide band O2 sensor to know the actual air fuel mixture going to the engine. That is the next step in gathering data here.

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This was the afternoon on November 17th at our airport in Florida, still pretty green down in the sunshine state. The season slowing down with the approach of the holidays and the arrival of cold weather up north, we will have many afternoons to test ideas and parts in the coming months.

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Wewjr.

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