carburetor

T66-4 page 8 is titled Carburetor Solenoid Shutoff for 1020 and 2020.

T66-1 page 1 is titled Stopping Engines with Electric Shutoff for 1020 and 2020.

Only JD parts can tell if they have a shut off solenoid to fit your zenith carburetor.

I drove a VW beetle 110,000 miles. It had problems shutting down, until I moved the oil cooler out of the fan shroud. It also ate an exhaust valve regularly because something in a keeper kept it from rotating and no one who fixed it replaced keepers. One mechanic said I should drive it harder to burn out the carbon that he found around the intake valve stems. But other than driving it longer each commute I couldn't drive it harder than full throttle through the gears. Then he suggested Marvel Mystery Oil. That just added a little blue tinge to the exhaust. What I worked out was a cooling regimen at each end of each commute. I ran it 6 or 8 blocks lightly loaded in 2nd gear at engine redline speed and the increased air and oil circulation cooled it down enough to not diesel. Cooling won't be as dramatic on a water cooled engine but idling at maybe 1000 RPM for a few minutes before throttling down to as slow as it will run before shutting down may reduce dieseling.

Gerald J.

Gerald J.

Gerald J.

Have you recently changed from generator to alternator?

Gerald J.

1. Carbon plug wires. I replaced them with copper wires with the ends soldered.

2. Worn out float needle and seat. The worst offender.

3. Donaldson precleaner top domed down, not up. Acts like a choke.

4. Dirty air filter.

5. Choke wire sheath not anchored near the carburetor, kept it from opening the choke all the way.

6. Ignition timing retarded 20 degrees from specification.

7. Junk in the intake manifold.

8. Champion plugs with too cold a heat range.

9. While I didn't have a problem with it, a leaky float can also cause excess fuel consumption as well as a fuel pump with a sticky pressure release mechanism. This year my fuel pump stopped pumping so I "ran out of gas" with the tank 1/3 full. An electric pump now does the work much better.

I fixed all those up and cut my 4020 fuel consumption from 400 gallons a year to 250 doing the same work. It stopped smoking like an IH diesel with a larger black cloud when opening the throttle after it had been idling.

I wanted to talk the to gas engine expert at the local JD shop but he said, "I have techniques but if you haven't replaced float needle and seat, I won't talk to you." I had float needle and seat in a sack in my hand, and I've not been back. I have it leaned enough it takes choking to start, even when warm. I think that's lean enough.

Its important that the centrifugal advance works or the engine performance and fuel consumption will suffer. It would be great if there was a part throttle advance mechanism like a proper vacuum port in the carburetor and a vacuum advance on the distributor, but very few tractors ever had that.

You can get an idea of proper fuel consumption by looking up the Nebraska tractor tests, perhaps in the book about them by Lester Larson. They give fuel consumption in horse power - hour / gallon. Most tractors do better than my 4020 gas at 7.96.

Gerald J.