Here is my Suevia 1.50, it is Serial# 492 out of approximately 500, it barely makes 1.20 sized power and at the weight you see it is no light weight. My take is that it would be a very reliable engine never offering to stumble or quit. I ran it on 5% Fox fuel with 20% castor. It has a roller bearing rear main and is very smooth running, that huge muffler is fairly quiet.

http://www.feintechnik.de/DOWNLOAD/motor.PDF Here is a link to a PDF file you can download and print.