ORIGINAL: Vern326
OK I am running the muffler that came with the engine. I don't know how much pressure it is actually putting into the tank. With this thought in mind is why I put an angle on the exhaust nipple. I thought the exhaust going across the end of the nipple may be causing a venturi effect and therefore a suction. This angle did not help or hurt the way the engine runs.
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Every once in a while, an engine gets out of the factory that is just a tad tighter than it should be. It still falls within the normal range, QC wise, but it will end up needing a little more running time in order to break-in. I suspect this is what is happening, Vern.
I bench run my engines and have for a long time, but every once in a while I used to get too antsy to run them in on the bench. I then saw a friend's test bench/break-in model fly some years ago. It was a Bridi Trainer 60, but it was heavily modified, just for testing new radios and breaking-in engines. I copied his ideas down to the T. Not only did it give me a fun model to fly, but it was very useful. After I flew the model for over half a decade, the friend that I copied my model from bought it from me. He campaigned it in many fun flies up and down the East Coast.
Since Bridi Trainer 60 and 40 models aren't available today, we won't talk about using one of them, but the Ultra/Ugly Stick models are perfect substitutes. When the engine quits on one of those prematurely, being a trainer type of model, the results aren't nearly as catastrophic as someone flying/hovering a 3D model close to the ground, if you know what I mean, Vern? <G>
Sorry, I couldn't resist.
Anyway keep us informed about how the engine progresses. Should you decide it is not for you, let us know when you list it for sale on RCU. Some of us like taming broncos.