breaking in my 75 ax and have run 4 tanks thru on the rich side so im trying to get things set now (still on the stand) and i think ive got it close but im kinda confused about a couple things (1) when i try to start it the engine turns the opposite way which is a sign of being too rich but() when i do a pinch test it dies right away without reving up the least little bit which is a sign of not being rich enough so what do i need to do?

Richen the high speed and don't prime it so much when you start. That's what makes it spin backwards when you start; doesn't have much to do with the high needle.

Yes, running backward is a sign of being rich, but that could be your prime. It has little to do with how the needles are set.

ok got it running and starting good now and the pinch test works just fine .....wondering now if its a little too hot ,when you shut it off how hot should it be to the touch should you be able to keep your hand on it or not ? that sounds like a dumb question to me ,and sorry if it is, but im just wondering

Not a dumb question. I just ran my 120AX and after a couple of minutes the engine was too hot to touch. I think somewhere around 250 degrees is fine, and that's hotter than boiling water.

I found with the AX engines that if I stop priming the engine just before fuel gets to the carb, it's just enough and starts on a single flip.

They are great engines; I'm really glad you're getting yours dialed in. It will continue to develop more power as you run another gallon of fuel through it, so enjoy!

If it starts backwards, get behind the plane quickly, hold it so it does not push backwards, and quickly open then close the throttle. It will most likely switch over to rotating correctly. (by quickly I mean don't try to hold the throttle open, and don't have to open it much, just quickly open it to about a quarter throttle and just as quickly, back to idle. If it stays backwards, try it again. Once or twice. You will get the hang of it. All of my AX's do that.

CGr.

Yes, the engine and muffler will get hot enough to burn you. Do not touch!

thanks guys im breaking in a 55 ax and a 75ax at the same time seems the 55 is not as near as hard but they both sound great now!!!

You can get a sense of how hot the engine is running during break-in by feeling the exhaust stream an inch or two behind the muffler outlet. The fingers get a bit oily but it won't burn them to take a quick feel.

Generally, use the lightest prop (lowest pitch and diameter) recommended by the engine manufacturer for break-in. Most ABC/ABN engines need only a tank or two before flying.

I find the larger the engine, the more time it takes to find a perfect transition. This is based on one 46AX, two 55AX, and two 120AX. It all works out in the end, though

seems the 55 was alot cooler as soon as i turned it off but im satisified with both of them tonight!

Bigger engines have more material to hold heat, and are burning more fuel per cycle. They even use a different glow plug. OS recommends the #8 up to a .61 engine, and the newly named #10 for over .61. Of course it's just a recommendation and you can use whatever makes your engine work the best. Long story short, it's ok that the 75 is a little hotter. As long as your in the proper RPM range and not running lean you are good to go.