Small Engines (Lawn Mowers, etc.): Deere Trimmer with Zama C1U H46 carb, zama carburetor, blowup

Question
John – I have a Deere trimmer with a zama carburetor model c1u – h46. It will start and idle but as soon as I give it full throttle, it will rev high and then fall, high and then fall. I have had the carb apart, installed refurb kit, soaked it overnight in carb cleaner, see light thru the main jet etc. I’ve checked the fuel line and filter. Checked the muffler and actually took it apart. Unscewed the gascap to see if that might be restricting air in.
I DO see in the exploded drawing that there is what’s called a “retainer” that looks like a small sleeve that slips over the carb ends of both mixture needles and goes down in the passage with the needles. Either I don’t have them on mine or I blew then off with compressed air and didn’t realize it. The LO needle can be in all the way and it still runs so I know that’s not right. I think its running VERY rich because when it revs high there is gas mist coming out the air intake unless the LO needle is almost all the way in. Maybe those retainers made the mixture needle seat and without them it is max rich.


Answer
It is hard to say with any certainty, but if it is flooding,
then the inlet needle or a welch plug is leaking, or soaking or blowing it out damaged something.
  External mixture screw setups shouldn't affect the running of the carb, just limit the movement of the mixture screws.

I have a homelite trimmer with a similar problem, which I believe is more ignition related, and since many John deere trimmers are Homelites, may be the same thing.  I have swapped carbs from other trimmers and it runs the same, so I believe it is ignition, but since
I rarely see homelites anymore, and this guy doesn't want to spend much on it, it has been in my shop a few months.

Let me know your model number so I can look at the blowup, and maybe come up with some other ideas.
Thanks

  Fish