How hard are the non ringed engines to tuned and keep in a good tune, even in differnt weather conditions. thanks

It makes little difference whether the engine is ABC or Ringed

The easist engine I have ever had to deal with , is a O.S 46. AX. It`s a no brainer engine.

after a slobbering break-in with a temp gauge and tach my 2 - 46 ax and 1 - 55ax are still running within 2 clicks of where i set them on the bench. Deadhead the carb, couple of drops marvel oil down the carb, cap and plug the carb, connect the pressure and the carb lines from the tank together [8D]

Non ringed engines don't need to be broken in slobbery rich. Ringed engines do!

I still have a 1980s OS 40 ABC FSR that runs PUUURFECT My Instructer set it after breakin and I never very from that more than 2 clicks I recently replaced the front of the housing ( the front of those bolted on) and put in new bearings (because of storage rust not wear) and its as good as new.

Fastsky is right. ABC/N engines need to get up to operating temperature to properly break in. This type of engine has a slight taper at the top of the cylinder. When the engine gets hot, it expands to allow the proper clearance. If it doesn't expand, your break-in may actually shorten the life of the engine by wearing the parts out faster. Beak in ABC/N engines only a couple clicks off the peak setting.

Now, to answer your question: there's no difference in ABC/N engines and ringed engines when it comes to weather. Be aware that cold, damp air may cause you engine to run a little leaner than normal, and adjust the needles accordingly.

Dr.1

Do not confuse ABC with some of the non-ring Iron Piston engines that you may encounter. An ABC can be a kind of bear at first few runs. Use a small prop and lean it out. Best racing engine I ever owned, I smoked it on the first run. (Not reccommended)

ABCs, as DR 1 stated, can be slightly damaged if broken in like a ringed engine. OTOH they will serve a long time as a very good sport engine, just don't expect to be out front in a Pylon Race.

Any engine needs consideration at the needle valve in changing wx conditions. For a given needle setting @ 70*, considerably colder air increases the molecules flowing into the same opening, therefore a tad more fuel is needed so open NV a tad. By the same token air at 95* has less molecules flowing into the carb, so some leaning is needed. OTOH if the air supply is humid, then water is replacing the oxygen, therefore additional attention to NV settings may be required. Hot and humid is bad. Cold and dry is good. Same for almost any internal combustion engine.

In glow engines where the temp is generally between 50--75* and humidity stays between 50-75%, the average sport flier will never know the difference without a digital tach.

Do not confuse ABC with some of the non-ring Iron Piston engines that you may encounter.

You're showing your age, Hoss. Are there still any of those being manufactured? I remember Fox had some very strict break-in rules that voided the warranty if not followed.

Dr.1

Yep, most of the Enya line up to the .40 size. And the Fox 35 of course but anyone who buys one of them knows what they need.

As for running in an ABC rich, I did a notorious experiment on a new ABC by running it extremely rich for 45 minutes to see what happened. The pinch stayed exactly the same as it was new from the box, the piston was unmarked and the only thing that showed signs of any running was that the lower rod bush was polishing nicely and only on the upper half.

I generally stick to ringed engines as I have a hard time remembering how to spell, "ABC."