My recommended break in procedure:
I like heat cycle method for break in. Heat the engine to 240 degrees or so and let it cool before even firing it. Engine heaters like a Competition heat work well but do not get it hot enough for break in. I will put the heater on it for 10-15 minutes and then heat it even more with a heat gun up to at least 240. If you have an engine heater keep it on the engine during break in to keep heat in the engine. You do not want the engine below 200 degrees at anytime when it is running. If you do not have an engine heater a can coolie works well keeping the heat in. Monitor temp frequently.
Starting up the engine I will blow into the exhaust pressure line to get fuel into the engine. With the engine up to temp and a good charged glow ignitor try and start it. It can sometimes take a bit because of the oils in the engine during assembly. On most engines they come from the factory a little rich and can be leaned out a half turn or so before even firing it up. If it does not wan to stay running lean it out, leave the glow ignitor on for atleast a couple minutes. If it dies when you take off the ignitor then it is either too rich or too cold of a plug. On the first firing only run a half a tank or less on the starter box at a high idle monitoring temps often. Stop the engine and let it cool. Repeat the procedure and run the rest of that tank. Stop the engine and cool it again, then run a full tank, you can run the second tank and after in the car on the ground. Be smooth with the throttle and do not use much throttle until the 4th or 5th tank. I like to see atleast 6-8 tanks before running it at the track. You can cut this in half if it has been lapped.
If the engine sticks at tdc carefully pry on the flywheel using the chassis as a pivot, also make sure the engine is not stuck after you shut it down. Always stop an engine by stopping the flywheel with a rubber object and never plug the exhaust to shut it down unless you have to such as a runaway.
Engine tuning 101
First thing to do when tuning is check the idle gap. It is very important that it be set correctly. Idle gap on most engines somewhere around .7mm or .030" is about right. Some more and some less but this is a good starting point. Most engines the idle gap is not set from the factory and is set wide so it does not stall with a rich break in setting.
Remove the air cleaner and restrictor. Probably the easiest thing to use is a std. size paper clip, most measure .7mm. With the carb slide closed the idle gap should be the width of the paper clip.
With the idle gap set you will use the low speed needle to get the idle set. Richer or counterclockwise will lower the idle speed, clockwise will lean it and raise the idle. Your engine should idle for 10 seconds without stalling. If it seems to be rich and load up after idling a few seconds it is probably too rich. It should load up and feel just a bit rich. If your engine does not come down to a low idle right away the idle gap is probably too wide. You will notice it revving in the air over jumps. You may need to lower the idle gap and lean the lsn some.
The high speed needle is usually set on the straightaway on the track. The engine should increase in speed as you lean it an hour at a time. New engines should be rich from the factory but to retune an engine you have raced before richen the hsn first before retuning.
All engines will be over 200 degrees when tuned, some as high as 275 deg. Argus like to run at least 250 deg. You should see smoke out the pipe down the straight but not alot.
The Argus A5, 23 A52, D52 all use the same carb. The R8 and R83 3 port both use a slightly different carb. Generally the A5, D52, .23 carb will have the lsn slightly in from flush with the housing. There is a chamfer and it usually is close to being about right where the chamfer ends.
The R8 and R83 the lsn should be out from flush when tuned in, about .5mm or a little more out from flush.
On all the Argus engines the factory Hsn setting is flush with the top. This should be a slightly rich setting and lean from there.
The factory plug works well for break in. I will usually change it out before racing with it. I like Odonnel 97t, 77t, Werks/Orion #5. If you use Os plugs the P3 is too hot, use a P4. If you use Os plugs stay with Os plugs as others may not seal after switching brands.