John Deere 420 garden tractor

These garden tractors all have something in common, they are powered with Onan engines. The Onans are decent engines but it is getting more difficult to find parts for any needed repairs.

Q: My John Deere 318 garden tractor with an Onan 18HP engine surges or pulsates under no load. When the PTO is engaged with any attachment the surge disappears? I bought it used last year and it is a great work horse.

A: It sounds to me like you have water or dirt in the carburetor. Take the top off and check for dirt or water. Take out the front jet toward the muffler, blow air through that orifice. Put it back together and adjust that air screw by the muffler and I would like to think everything now would be O.K.

Q: I have a Simplicity 9020 garden tractor with a tired Onan engine. I’m wondering about replacing the engine, or rebuilding it. Are parts still available for Onan?

A: Onan is slowly going out of business as they did not build an engine to pass our pollution standards. Our 23 horsepower Vanguard engine is by far the best way to go and is the best air cooled engine that money can buy.

Q: I have a 1987 John Deere 420 garden tractor with an Onan 20 HP engine and it surges. When I remove the air cleaner I can see the fuel being squirted into the carburetor when a surge comes. I have rebuilt most of the motor and installed a new carburetor and it is still doing it. Do you have any advice? Do you have a repower in a Vanguard?

A: It sounds to me like you have a leaking intake manifold. The way they have built the intake manifold is a bad design. Yes we have a Vanguard V-Twin overhead valve engine and made to order installation kit for your application.

Q: I have an Onan P218G with electronic ignition in my John Deere 317 garden tractor. It Runs great. I replaced the rings about 2 years ago and so the engine is clean inside.

When I start it, it often kicks back. Sometimes it locks up the starter. When it does this I have to take off the side cover and pry on the cooling fins to turn over the engine a small amount to get the starter to work again.

I took the engine out and checked to make sure the flywheel key was not broken off, it wasn’t. I replaced the spark plugs and this seemed to help some but now it is kicking back and locking up the starter again. It even unscrewed the nut on the starter twice and I had to take the engine out to put the nut back on.

Do I need a new electronic ignition?

A: When you had the engine out did you check the 2 holes in the block where the 2 starter bolts go through? You need to make sure one of those holes or both are not cracked or broken. You should replace that electronic module inside the flywheel. Also there is an electric ring slid on the crankshaft, that should be inspected and or replaced.

Q: I am the owner of a John Deere 420 garden tractor. I have been very happy with it since purchasing it used 6 years ago. Recently I have been having a problem with it losing power and shutting down after running for about 20 minutes. After checking it I discovered the spark is not there. What could be causing this situation? I think it is the Ignition coil or stator, can you confirm this for me? It is a P220G with an electronic ignition.

A: It would not be the stator because that has nothing to do with the ignition system, and yes it can be the ignition coil and or the ignition module located inside the flywheel.

http://www.jimsrepairjimstractors.com 1-800-618-8738

John Deere 317

Some quick answers to small questions about small engines and garden tractors.

Q: Can you help me with balancer timing on a Kohler K341 engine? There must be a better way than counting crank and balance teeth clock or counter clockwise rotation. Any help would be great.

A: Kohler makes a tool for timing those 2 balance gears. Check with a Kohler dealer and they should be able to help you out in getting one.

Q: How fast is a 18 horsepower engine?

A: This engine runs at 3600 RPM’s at full no load high idle.

Q: What size battery will my John Deere 317 garden tractor need in order to try to get it working again?

A: The correct battery size is a MT 26.

Q: My John Deere tractor has an 18 horsepower Onan engine and it will not recharge the battery. What part do I need? Is it a starter/alternator combination?

A: No, it is not a starter alternator combination. Sounds like you might have a bad rectifier.

Q: I have a Cub Cadet 1440 with a 14 hp V-Tech Vanguard engine.  Yesterday I noticed an oil leak at the front crankshaft seal and a noise I assume is from the front bearing.  From the diagrams, it looks like the bearing is in the front cover directly behind the seal.  Can this bearing be replaced with the engine in place without breaking it down and or pulling the front cover?

A: Yes, you can put the seal in without removing the cover, but it is a hard job.

http://www.jimsrepairjimstractors.com 1-800-618-8738