Why You Should “Always” Use Starter Fluid
… To Start Carbureted Gasoline Engines After a Layoff
Summary: Use starter fluid on all carbureted gasoline-powered engines to start them after they’ve sat without use for more than a few weeks. Don’t waste time pulling the starter cord more than twice — go right to starter fluid. This might be even more important when your gasoline has ethanol in it, which gums up carburetors.
I’ve got a mid-size suburban home with several gas engine things, almost all trash-picked or second-hand. In fact, the only store-bought one is a lawn mower from Hechinger’s in 1990, and it still runs. But it wasn’t until I got back into dirt-bike riding that the wisdom of starter fluid sunk in.
My Kawasaki is a great dirt bike but it’s very hard to start after not being used in the winter. The typical advice is “don’t do that!” In other words… 1) drain the carb before wintering; 2) put additive in the gas tank; 3) fill the tank all the way to displace air that will hold and condense out water; 4) you should have bought a fuel-injected bike; 5) you shouldn’t have bought gas that has gummy ethanol. My personal workaround was to try to start it every month. But I quickly learned that using starter fluid, by spraying it into the air filter while cranking, started it immediately in the springtime… without all that bullshit “usual advice” stuff.
Now I never struggle starting that piece-of-shit Craftsman edger that I got from a junk store. But it did teach me what the simplest possible carb looks like. Wow, just one simple port above a float-bowl full of gas. And by the way, that trash-picked chipper-shredder? Even though it’s this story’s poster child, that particular machine actually never needed starter fluid. That Briggs-Stratton engine amazingly starts every spring and fall in a couple of pulls, for 25 years! I might have replaced the coil once.
Ethanol
I read this on the internet so it must be true. Apparently fuel injection took over right around the same time that the US started putting ethanol in gasoline… because ethanol makes gas more prone to gumming up the super-small ports in carburetors. And injection reduces or eliminates that problem. Whatever the case may be, the logic for carburetors is the same or more so due to ethanol adding more gum.
Why Starter Fluid Works So Perfectly
The little holes in a carburetor are deliberately very small — pinhole small — to create an aerosol — a mist — of gas and air. They introduce this mist into a 1-inch wide tube (not small at all!) that goes from your air cleaner to the engine. When you pull on that starter cord (or kick, or crank, or whatever), you are trying to spin the engine fast enough for the cylinder to create enough vacuum pressure to suck the gas through those little holes to aerosolize it. That’s a losing battle after any layoff.
But when you spray highly combustible starter fluid into your air filter… it doesn’t go through any teensy-weensy holes; it goes right through a wide-open 1-inch tube!!! I’m not sure, but even if your choke is active (flapping the 1-inch tube closed) I have a feeling the starter fluid gets 100 times more fuel through than the little carb ports. And once the engine is spinning on its own for a few seconds, burning only starter fluid, some serious vacuum suction is produced… a lot more than you pulling a stupid string.
Use starter fluid almost immediately
- So don’t fart around. Use starter fluid almost immediately.
- Some devices hide the opening to the air filter; you’ll figure it out.
- Buy at least one extra can all the time, so you don’t quibble.
- Consider putting a ‘port’ in some machines. I put a tube on my Kawasaki, with a little filler plug on a zip tie (to not lose the plug). I was gratified to see someone else also reached this conclusion, and they had an even better ‘port’ solution, drilling a hole into a convenient spot in the airbox, and using the starter fluid with a spray tube. But make sure to plug the hole.
