John Deere 318 – Your Top 5 Troubleshooting Questions Are Answered

Below are the five most common questions we’re asked regarding John Deere 318 troubleshooting. As well as the 318, the answers to each of these questions should also apply to the following lawn and garden tractor models:

If you’re looking for more general resources, you may find the following links helpful:

1. My 1989 John Deere 318 runs great, but it stalls after mowing for about a 1/2 hour and won’t restart until it cools off.

A: 1987 and newer 318’s use a Onan p218g engine with electronic ignition. Normally, that problem is caused by the ignition module that is located behind the flywheel.

2. The engine on my John Deere 318 is surging and will only run smooth if I pull the choke.

A:There are a few things that will cause this issue. The most common is a dirty carburetor – normally dissembling and cleaning the carburetor will cure this.

Another cause for this is that air is being drawn in someplace, such as a split intake manifold. The Onan engines in the John Deere 318’s used a 2-piece manifold that can separate.

3. When my 318 gets hot, the mower deck will not engage.

A: Sounds like your PTO clutch is out of adjustment – the proper gap setting is .018. It is is set by tightening the 3 spring loaded nuts around the clutch. For a quick fix, you can tighten each nut equally about a 1/8 of a turn and see if that is enough to get it to engage. This also applies to other John Deere lawn and garden tractor models, including the 316, 318, 322, 330, 332 and 430. 

4. The starter on my 1990 318 doesn’t always engage. Sometimes I have to turn the key 3 or 4 times to get it to turn over. I already changed the starter but it still has the same problem.

A: The way 1986 and newer John Deere 316, 318 and 420’s were wired from the factory did not provide a full 12 volts to the solenoid when you turn the key. Many times, people will replace the starter thinking that is the problem.

The real cure for this problem is to add a relay to provide a full 12 volts to your starter. John Deere offers what they call a starting improvement relay kit – part number AM107421. This includes the relay and wiring harness needed.

5. My Deere 318 won’t start. I have spark, but no fuel. I’ve already replaced the fuel pump, but still no fuel. What would cause this? 

A: Many times this is caused by bad fuel lines – even if they look ok from the outside, they deteriorate on the inside. The main reason this happens is because today’s gasoline contains 10% or more ethanol. I recommend using non-ethanol fuel or treat your fuel with a product such as Startron.

If you enjoy tinkering with your John Deere – or you’re trying to troubleshoot a problem you’ve been having – I recommend getting a copy of a John Deere User’s Manual to reference. Try searching online if you don’t have one already. For instance, this comprehensive manual for the John Deere 318 also covers the 316 and 420 as well – it’s available here, at

What about you? Did you ever encounter a tricky problem with your JD 318? How did you figure it out? Let us know and we may feature it in an upcoming blog post!