ORIGINAL: bkdavy
Sometimes the glow plugs (not driver) get fouled by small metal particles that come loose during break in. If a new engine is running poorly, sometimes it helps to put a new plug in. As previously mentioned, go with a hot plug (OS A3).
bRAD
Well I feel bad for the CEECRB with the magnum. However, I will have to disagree with everyone who has bashed this engine. I have OS and Super Tigre engines and I prefer the Magnum engines hands down. I have actually switched all of my engines out and am running all Magnum engines. I have the 46, 52 and 91. That being said I have only messed with the 2 strokes, I know nothing about their 4 strokes.
As far as the simplicity of breaking this engine in and getting it set right was as simple as doing the initial break in as written in the directions. I have never touched the low end on these engines. I have only adjusted the high end adjustments and use my trusty tach. After my break in I only have to touch the high end because of the humidity/temperature. I also use OS 8 glow plugs with all the engines. I absolutely swear by these engines.