I bought a powermac brand generator last year and had it converted to Natural Gas. It was able to run on NG, but only an choke stuck midway. I asked the mechanic about this and he ensured me that NG converted generator do run on choke and this is normal. Anyway i didn't believe him and asked the opinion of other mechanics as well but they didn't point out a fault as well.
Anyway i searched a lot over the internet and found that running on choke means lack of vacuum suction and this was exactly the case with my genset. Also i found that the gas inlet in the carb should be at the center of the venturi for optimum vacuum suction. Whereas in my carb it was no way near the center but instead at the mouth of the carb. Therefore i tried to correct this fault by drilling at the center of the venturi and installing the gas jet there. Now the carb is generating quite strong vacuum in the NG jet and i am able to run the generator on NG without choke.
However, it has developed another problem. It starts fine, runs fine but when loaded to around 30-40%, it starts surging randomly up to the point where it feels like it is just going to die any second. This random surging goes on for like 5 minutes eventually resulting in engine shutting off. At this point, if try to start it again, it starts fine, but again it surges randomly and then turns off again in a few minutes.
The only thing i did was cleaning the carb, drilling the hole at the correct place and installing a new demand regulator (gas kit in common language).
Can anyone help me in identifying the problem?
