Flames!

[63DH8]

I'm not too familiar with the two cylinder John Deere engines. The other night, I started my 420C to get to the master link on the track. I noticed flames coming out of the muffler's exhaust. This got me to worrying about burning the valves. Is the timing off, or could the cause be valve adjustment being off? Or is this normal?

[Willyr]

If it is a straight stack and your doing it at dusk with little light, some dull flame is normal. That being said, if you have a bright flame (did you wind it over getting too much choke?) it may be burning off some extra fuel. No, bright flames are not normal.

[440 iron popper]

It happened to me last year. After a while pushing snow, I saw quite good flames coming out the pipe! Enough to shut it down. I searched for a cause... My alternator died. The battery discharged to around 8V. So the output of the ignition coil was lower, weaker spark. I guess unburned gas from bad combustion reached the hot stack and finished to burn there. I tought I created a 5 strokes engine... I fixed the charging issue. After that, no more flames.

[63DH8]

Thanks guys! I think it was because the tractor was still cold, and there was unburnt fuel in the system. You guys are great!