3020 Gas excess exhaust idling

We have a 3020 John Deere gas that we purchased a few months ago. Was sputtering under load, got that figured out but still having problems with excess exhaust when idling. 90% sure it is gas problem and not oil. Any ideas? Have tried manifold, choke, carb, but open to any suggestions. Thanks!

Those tractors were known for overfueling at idle or light load. Do you have the Marvel Schebler carb or the Zenith?

If you do not have a GOOD older tractor mechanic nearby, you might try giving Robert"s carb repair a call. They offer an updated carb, as well, they aren"t cheap but improve the situation a LOT.
Roberts

Welcome to the issues JD gas engines have with the "NEW" gas. I used a JD gas 3020 for years to feed live stock. About 8-10 years ago I got so tired of it NEVER really running right that I sold it and replace it with a diesel.

The trouble is the fuel does not burn the same as the pure gas the engine was designed to run on. The carburetor is running too rich for idle but the tractor will not take throttle if you lean it down enough to run clean at idle. There is really no total solution. Here are some things that will help.

1) Switch it over to an electronic ignition. The hotter spark helps.

2) Run hotter spark plugs.

3) Buy the best non alcohol gas you can afford.

4) Idle the tractor as little as possible. I finally set the low side on mine at 1000 rpm. The spark plug life doubled.

5)If you have the MARVEL-SCHEBLER carburetor replace it with a ZENITH one. They will run better.

The only total solution is to switch to a diesel JD 3020. You are finding out why the JD gas tractors are so much cheaper than the JD diesels of the same model.

Truthfully if I had to run a gas tractor it would not be a JD. The IH and Ford gas tractors run better.

Coolant temperature? There are ding dongs that throw away thermostats and run without. Or install 160F stats. Use a 195F stat.
Ignition timing at startup, idle and full rated rpms?
plugged intake system?
Choke blade partly closed due to wear in linkage?
Compression?
Valve lash ?
An intake manifold leak, intake gasket leak or carb gasket leak would be no surprise.

Thanks everyone for your replies. We bought this tractor about a month ago and knew we would need to do some "tinkering". We have had excellent luck with newer carbs from Marks Carb repair out of MN. We are waiting on water pump now before we can start trying any of your suggestions. Thanks again. Will keep you posted when we get it back together.

problem may be accelerater pump in carbureter check valve may be leaking