ORIGINAL: 1QwkSport2.5r
ORIGINAL: earlwb
Well, the last new Fox .60 engine I bought and ran, worked pretty good right out of the box. I normally just use 5% nitro glow fuel, so I typically don't have the problems that others do, trying to use higher nitro content glow fuel in the engines. I ran a few tanks of fuel through it with a 11x7 prop and the stock muffler. By then it was loosening up pretty good. So I put on one of my Performance Specialty tuned mufflers using a bridge adapter I made. The engine ran as good as my Rossi .60 engine does.
I like to heat cycle the engines when I break them in, I run it for a while, then let it cool off, run it, cool it off, and so on several times. The first run is extra rich and I don't try to lean it out much or run it full throttle either. Then on each subsequent run I lean it out a little more. Eventually it gets to where it'll hold full throttle good with the needle set a little on the rich side.
Does the Fox Eagle IV .60 come with an ABC piston/liner or is it ringed? Either way, doesn't past wisdom say 2-strokes should be ran WOT to break-in? The exceptions being 4-strokes and the oddball engines like the backwards AAC K&B Sportsters...
I'm not the expert here. But break-in for ringed engines is different than ABC/ABN/ABL/AAC engines. The ringed engines you want to run extra rich and gradually lean out over a longer period of time, as earlwb mentioned. That allows the piston ring to gradually wear in to perfectly match the cylinder. The ABC/ABN/ABL/AAC types need to run full on (not super rich, but only slightly rich) for very short bursts of time and then immediately shut them off to let them cool down completely. The heat cycling allows the cylinder pinch to open up and not undergo excessive friction that would cause the chrome or nickel coating to wear off. The worst thing you can do to an ABC/ABN/ABL engine is to run it super rich and cool during break-in. All that does is prevent the cylinder pinch from opening up by heat and causes excessive friction that would ruin the liner coating, especially the soft nickel.
But, the larger (60 and 74) Fox engines are now all ringed (except the expensive ceramic control line 60). So, run-in is as earlwb described.