If you have the room get a walbro ( model wy) for your Brison engine. The advantage of a wy is that they give a very even air/mixture throughout all throttle settings. These carbs are a little bigger, so you may not be able to use it in your cowl setup. I bet you are flyng a scale plane at lower speed and the engine does not sound good at those speeds. Thanks Captin John P.S. you can get a Walbro service book, that shows operation and how to tune or rebuild the carbs. Very nice book. Phone 517 872-2131