I purchased a OS 75 AX ABL engine not long ago (10/5/07). I tried to follow the recommended break-in procedure -- run rich -- run lean -- but found there was essentially no difference in engine RPM to be achieved by adjusting the needle valve. The engine never reached what I would call a two cycle "wine". I have run two tanks of fuel through the engine and have found it very easy to start. While I have been doing this model stuff for some time (over 60 years) I have never had a ringless/close tolerance engine -- which could account for my confusion. Do I simply need to run the engine more? This is strange!
OS 75
Mar 08, 2008
1 Replies
Yes more time and fuel required. The ABC car engines that I typically play with need at least 5 or more tanks through them at WOT to start to run them in before they go round the track and then we start to lean them out over the course of another 5 tanks but still keeping them rich and with a full cool down period between every two tanks (faster break-in that way rather than between every tank). The engine will tell you it is almost run in by leaning out as it gets looser, very strange to see it happen: the car does one lap and you're struggling to accelerate and the next lap it's trying to change gear on the main straight all without touching the mixture!
Chris
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