FS-91 Update

After making a new “lanova” cell I attempted to run the engine. It started and ran but was not happy. I sleeved the throat of the carb, but this did not improve things significantly I was able to get about 6500RPM out of it. The carb needles were very hard to adjust and it wouldn’t run on even standard 35% ether fuel.

I had a Rossi slide carb from a car .12 or .15 engine with a smaller bore and made a straight intake manifold to mount it on the engine. After a bit of fiddling with the needles it was running. After several tanks I was able to dial the carb in and managed to get some tachometer readings. The best running seemed to be with very little ether in the fuel, but it still wasn’t the best. I did get ~7400 RPM with a Graupner 16×8 and about 9800 RPM with an APC 13×9. Idle with the 16×8 was an incredible 1800. It would actually run slower but sounded awful as it missed, but kept running.

Now to figure out what modifications are needed to the original carb to make it work. There also seems to be an issue of operating temperature variation in this engine. I think I can work it out with proper cowling in the airplane.

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