Welcome deere john,
I believe the ‘jets’ are viewable once the float is removed at the base of the carb.
IMO, if it runs rough with the choke partially closed….and keeps running, then you have dirt or debris blocking the main jet.
I have had great success (lately) with non-serviceable style carbureators by removing them, removing the bowl, float and needle and spraying **Brake Clean solvent FIRST (keep away from painted surfaces and remove the rubber bowl gasket!). Every mechanic I‘ve talked to lately, has complained about the effects of ethanol additives in our gasoline, and how they interact with moisture (h2o) and produce a syrupy gel that hinders fuel flow, clogs smaller fuel lines (like chain saws) and eventually block the fuel from flowing freely to the needle and seat.
I just finished my Murray lawn tractor, Husquvarna chain saw and Bolens RAT (rolling articulated string trimmer) using the above method. Three different styles and brands of engines, and even though I used fuel stabilizer, the ’snotty’ junk was deteced in all the pieces of equipment.
This is just a suggestion, but if you have space to install a high grade, viewable, in line fuel filter you can monitor the rates of fuel consumption. Watching the filter fill-rate while the tractor is running, often shows immediately any differences in flow to your carbureator. And in certain situations, if the fuel filter empties, or cant keep up, then you know you have a fuel flow problem up stream like a collapsed fuel line or trash in the tank.
**Brake Clean solvents are under much higher pressures than carb-spray. Be sure to remove rubber “O” rings from the fuel bowl as Brake Clean tends to stretch the material…permanently.
Mark
