Should Preppers Know how to Fix Small Engines?

man repairing a lawnmower
man repairing a lawnmower

Last week, I pulled out my old wood chipper to chop some fallen limbs into wood chips for our raised beds. I bought it more than fifteen years ago, used it for a while, and then gave it to a friend on a long-term lend. When he heard I was moving, he gave it back. It’s been sitting under my deck ever since.

The good news was that there was no gas in the tank or the carburetor, so he had stored properly it. The oil was full, but dirty. I decided it was sufficient to let me start it, so I grabbed the pull-cord and gave it a yank. Instead of the engine turning over, the entire device slid towards me. The engine and flywheel would not turn over.

If you have ever had this happen with a lawnmower, you can guess the problem: something was blocking the blade. Perhaps this is why my friend was so willing to give it back! I had to remove the housing of the shredding/chipping assembly and use a wood chisel and hammer to bust up a big chunk of wood that was jammed in there, locking it up.

I reassembled the chipper and gave the cord a pull. The 10-horsepower Tecumseh engine now rotated just fine, so filled the tank, turned it on, set the choke, and pulled it again. It wouldn’t start. I tried all the choke settings and it wouldn’t even catch.

Diagnosing the Problem

Knowing the problem was either no fuel or no spark, I checked the carburetor bowl and there was gas in it. It looked clean, no sign of old gas that might have gummed it up.

I unscrewed the spark plug and while it was dirty; it didn’t look bad. I tested it for spark. Ah ha! No spark. That meant it was probably the ignition coil. That’s a common repair, but a bit of a pain. I had to drain and then remove the gas tank and then unbolt and remove the engine cowling and get down to the flywheel.

In a small engine like this one, there is a set of magnets on the flywheel. When the flywheel rotates, the magnets pass under the coil, generating electricity. This flows from the coil, down the spark plug wire, to the spark plug itself where the spark ignights the fuel. There is a ground wire, which I disconnected to be sure it wasn’t grounding out. Still no spark. I sanded some rust or corrosion off the magnets, but it didn’t help. I would have to buy a new coil, so I removed it and took it inside the house.

Ordering Parts

I punched in the number off the original part and found multiple replacements available, running from about $17 to $49. I read some reviews and ended up buying one off Amazon for about $24. It was a Chinese clone, but it was for my engine model number. It had good reviews over multiple years and a highly-rated seller. While I was at it, I ordered a spare air filter. There was one air filter that came with a spark plug, so I got that model.

All the parts came earlier than expected. I guess the supply chain is working fine.


Installation was a breeze because I had disassembled it just a few days prior, and I still remembered where everything went. I used a business card to set the air gap between the new coil and the magnet. I rotated the flywheel, and it moved smoothly, no scraping. Then I tested the assembly for spark, but there was still no spark.

Frustrated, I put my tools away and came inside to watch some YouTube videos on small engine repair. Then my neighbor called about some gravel we are getting for the road, and I mentioned my problem. He came over and checked my work. We got out my multi meter and tested wires for continuity. Everything seemed fine. We used the old spark plug and the new one, but there was no spark. He said I must have a bad coil and suggested I avoid cheap Chinese-made no-name parts.

The engine in question is a fairly common model, used on generators, snow blowers and other devices besides the chipper, so there are plenty of videos on how to repair it. That evening, I was watching more videos, and one fellow said, “Make sure you don’t put your coil on backwards.” Hmm. I don’t think I put my coil on backwards. I looked at the exploded parts drawing and it looks correct, but I’m going to reverse it and see what happens. Boy, that would be an easy fix! I would laugh at myself, but I would also feel relieved.

Also, while working on the engine, I noticed that the air hose running from the choke into the engine had a split in it, no doubt having deteriorated over the years. This would be a problem if I had spark. That, at least, is something I can pick up locally.

So I still have some work to do.

Spare Parts for Prepping

This experience made me re-think the spare part have one hand for my other devices that use small engines. For my Stihl chain saw, I have two spare bars and about seven chains. While I have one spark plug, I do not have an ignition coil or other parts. I have no spare parts of any kind for my generator or my Stihl string trimmer.

In a post-SHTF situation, I doubt I’d be wasting any gas on my weed waking. I would want to focus on cutting firewood, which is why I have parts for the chain saw. I also have plenty of bar and chain oil, oil to mix with the gas, and a couple cases of 10W30 motor oil. My last chain saw lasted 16 years before it gave out and never needed a single repair. Hopefully, I will have that kind of track record again.

The generator, however, is a question mark. My thinking had been that we would not be in a situation where I would have plenty of gasoline to run the generator but no source for spare parts. Given our current tensions with China and the supply chain issue, I need to rethink that. If China invades Taiwan and we go to war, we could find ourselves in a situation where we have gasoline from domestic oil wells but are not getting spare parts from China. In that situation, I should probably have some spare parts on hand.

It’s important to note that we keep the saw, weed whacker, and the generator indoors and use them occasionally. The wood chipper was unused for years and stored outdoors for at least half of its life. Sure, it was under a tarp, but that doesn’t stop humidity and heat from causing deterioration. Maybe the lesson is to store small engines inside, but as I said yesterday, we have no outbuildings, and our garage can only hold so much.


We should all know that “one is none and two is one.” This engine issue drove that home. Supply chain issues may be with us for some time, so look at equipment you rely on and decide what spare parts you might want to keep on hand. They might come in useful whether or not we experience a collapse.