I'm a mechanic encountering a Hijet (1991 s83p is the ID I was given for it) for the first time - a guy has been trying to get it running for months, and finally sent it to me. There was no spark, after one or more people messed with it to get it working (new coil, new distributor, no way to know if either was necessary). Turns out someone had "fixed" the wiring to the coil, resulting in constant 12v on both sides of the primary. No idea what the logic was there, but that's what happens... After that was repaired, it fired up - and immediately started racing. The tach on my timing light is telling me it's doing 6k rpm, don't know if that's accurate but she's turning way too fast. First thought was throttle was stuck open - it isn't. I don't know enough about these carbs to make a reasonable guess, so I was wondering if anyone has any ideas. I backed what seems to be an idle screw back far enough that the throttle isn't touching it, so it's all the way closed. Key thing here is, I have no idea whether it's an issue that it developed on its own, or the results of someone "fixing" something else.
While not a mechanic by trade, My mechanic who is about 55 years old went to mechanics school. It was during the days when you got special training in carbs. So he was ASC? specialized / trained. He is able to look at the carb and without any kind of manual tell me what every feature and function does on the carb. So, perhaps an older Carb guy will be able to answer this question. At least that is mho. Best luck and let us know what you eventually find out.
Thanks, I ended up letting him deal with it himself, he was happy to just get the electrical done at a shop.