ORIGINAL: TimC
boxbeam or Cambo, I'm curious what the manual says about break-in. I suppose it's different than the normal four stroke. I tried to download the manual but my Adobe is acting up.
The manual finally downloaded and I don't know if I agree with the instructions or not. "At full throttle, peak the engine for 5 seconds then richen 1 full turn of the high speed needle......."
This would result in a very rich condition which goes against the accepted method for breaking in an ABN engine. I'd like to hear what other members here think.
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As has been pointed out, this is an ABN engine, which usually doesn't have that much pinch at TDC, such as with an ABC engine. I doubt that doing as they advise would be as damaging to this engine as it would be in a high ratio tapered engine such as a tight ABC engine.
Conversely, while I suspect that their way might break the engine in a little sooner, I can't see where it would hurt to treat the engine as though it were a pure ABC engine and not quench it with lots of fuel by running ultra rich. It "might" just take a little longer to settle in.
It's just my opinion, but I suspect that OS has chosen to fulfill the needs of the instant gratification crowd, while disregarding those that love engines that will last twenty to thirty years without a major rebuild. Giving someone an engine that is quickly ready to hover can be a serious advantage in today's marketplace.
I doubt that the folks at OS do not know what they are doing. Even the latest crowd. <G>