Hello!
I´m the Swedish importer of MVVS engines since
the last 10 years.
All modell engines and certainly all MVVS engines runs best on all syntetic oil.
Here in Europe 15% oil is what most of us use....yes you read right ...just 15% oil....some even use as little as 6-10% oil.
The oil most used is an oil from Graupner ( Big hobby product producer) called Aerosynt II and Aerosave. But also the French manufacturer MOTUL makes an oil for glowengines called "Micro"
which I myself recommends. Motul also makes oil for bikes and cars.
Forget about castor oil.....!! The modern syntetics work much better ...and give no carbonbuild up!
As I am and old ( 48) pylonracing guy I was using only castor oil (20%) in my racingengines but some years ago I saw what a difference the syntetics oil did to our engines and have since then converted ....at least when I fly my sport engines and not my racing engines (the rules in international pylonracing does not allow any other oil than 20% castor oil).

You will be suprised what a diffrence 15% Motul "Micro" oil or the other syntetic oils will make to any glow engine......
Try it and you will never return to 20% castor oil again!!


Regards!
Jan K
Sweden