I had to have the carb rebuilt, it was an odd duck hard to adjust. No I haven’t tried diesel, Marvel M-O yes, but not diesel...
Over time, I’ve had to pull the bowl, dump out slugs (water and slime)and only if I’ve left fuel in them. Maybe replace an occasional needle and seat or sunken float.
If you know a guitar player, an old “High E” string comes in handy for cleaning little passageways.
The best thing invented since sliced bread, is the Briggs and Stratton “Magnetron” ignition coil. It eliminates the points and condenser, and works just fine wet.
Every rig I’ve got now has one, as it makes the machine smooth, reliable and easy to start. The snow blower is never even started unless it’s below freezing, and then I seriously rely on it.