Last night, a friend came over to help me shoot some video. He wanted me to crank over my 1986 Grand Wagoneer to see if it ran. I doubted it would, but I gave it a shot anyway. While I was cranking the engine over, he picked up a can of starting fluid. Big mistake.

From inside the Jeep, I kept hearing the engine fire every three or four seconds. “Hmm... this is odd; it seems like it wants to fire even on the 12-year-old gas.” Then I heard a misfire and my friend yelling “Fire!”

“What the hell just happened?” I almost had time to think as I sprinted 100 yards into my garage to grab my fire extinguisher. Luckily, another friend of mine had joked about my Grand Wagoneer a few days prior: “Hey Dave, remember, your fire extinguisher is in your Willys,” so I knew exactly where that red propellant-filled tank was.

I hustled back to my Jeep to see my friend trying to fan out the fire that was spewing from my carburetor. I popped the pin from the extinguisher, and began coughing as a white cloud of dust ended the drama.

My friend admitted that all those times the engine was “trying to fire” were a result of him spraying copious quantities of starting fluid directly into my carb as I cranked the engine. So essentially, I was flooding my motor with stale gas, and he was hitting it with ether.

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Anyway, now seems like a good time to talk about the dangers of starting fluid. First off, never spray the stuff into a carburetor while the engine is cranking. Ether is extremely volatile, so it’s not surprising if you get a backfire, and then you’re essentially holding onto a grenade. Spray it into the carburetor first. Then crank the starter.

And by god, be light on the starting fluid. I know, it’s tempting to joke about “feeding the motor some go-juice,” but Ether not only tends to combust violently (which could, theoretically, damage your engine’s internals), but even with the “upper cylinder” lubricant that’s in it, starting fluid can and will seize your motor if you use too much.

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See that Suzuki GS550 engine in the picture above? It’s been sitting on the shelf in my garage for a long time, because about four years ago, I decided to spray starting fluid directly into the cylinders to try to get that sweet Japanese inline-four to fire up. After it failed to run, I went on a two week-long “hot trip” (I was running tests on the then-new Jeep Cherokee KL), and returned to find my motor completely locked up.

No amount of Marvel Mystery Oil could fix that problem. I hung off a two-foot breaker bar, but that piston had become the sword in the stone; it was forever locked in place. Essentially, the starting fluid I had sprayed into my engine and left sitting for two weeks had acted like a solvent, wiping oil off my cylinder walls, and causing my piston rings to “bite” into their bores.

That locked motor taught me a valuable lesson about the dangers of ethyl ether-based starting fluid, and I’m sure my friend learned a thing or two from my now-charred AMC 360 V8.

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So yeah, for the sake of your health and your engine’s health: take it easy on the starting fluid. If your vehicle’s not running with a light squirt of “the good stuff,” you’ve got other problems that starting fluid will not solve.