ORIGINAL: asmund
15% synth, 5% Castor and 5-7 % nitro.
I monitored the temp all the time and the hottest it got was 212º Fahrenheit, mostly around 180.
...I don't consider the engine fully broken in yet, but ready to get airborne.I will try to get a 12-4 tomorrow and give it a try too.
Asmund,
You are using too little Castor oil in your fuel!
From my own experience and others', including Pé's, these engine run much better with a lot of Castor oil in the fuel.
It is not a minor difference, but a totally different experience.
Anyone who experiences running difficulties with his up-to-15 cc MVVS and changes to high Castor fuel, within 2-3 tanks the engine transforms! I don't know the exact reason for this, but it is simply so!
Monitoring the exact temperature is redundant! You must only keep the engine somewhat richer than peak. That is all.
Give the engine another 2-3 tanks of with
over 20% oil, mostly Castor.
Use a 10x7, or a 10x8 prop, for better cooling and then switch to the 12x4 for flight.
Patience is the key word here.