Tag Archives: Carburetors

Carburetors are Black Magic

For those of you not familiar with history there was a time when gasoline powered engines of all stripes did not easily start on the first attempt and, depending on the weather, required a particular dance to maintain a smooth idle.  Before electronic fuel injection made our lives easier by eliminating carburetors from our lexicon we were forced to adjust chokes to fine tune a fuel air mixture and worry about things like jets getting gummed up with deposits from gasoline.

Anyone who waxes nostalgic for the days of carburetors is either lying, has no idea what a carburetor actually does, or enjoys spending afternoons swearing at small brass tubes with small holes punctured in them.  I am going to posit that most people are in the first group.

Carburetors are like black magic.  Somehow this crude assemblage of bulbs, floats, jets, needles, and what not is capable of mixing fuel and air into the appropriate ration to ensure combustion in our small engines.  On most modern small engines the manual choke has been eliminated in favor of automatic chokes using a variety of bi-metal arms to ensure operation.

When it is spring time and you wander out to garage and the mower does not start.  Is it the spark plug?  Maybe, considering my spark plug looked like this compared to a brand new spark plug:

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A few minutes with a 5/8” socket yielded…nothing.  The same sad burble as before.  Maybe the engine was not getting any air?  Given the condition of my old air filter that would not be unthinkable:

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Less than thirty seconds later I got…nothing.  This is the point when most people give up and load the mower for a trip to the small engine shop.  I come at this from a slightly different school of thought that says, “If you can’t fix it, you do not really own it.”  Some take that to mean that you have the option of having the item repaired by a professional as opposed to the item being essentially disposable.  While this is a laudable goal for all products, I want to control a little bit more of my destiny.

When your mower will not “turn over” in the spring try this trick.  Remove the air filter and spray some starter fluid directly into the air intake.  If your mower starts, but dies after a few turns of the crank it likely means that there is a problem with your carburetor.  This, dear friends, is within the skill set of a decently mechanical person, especially given excellent videos like this one on YouTube.

Here’s the deal.  I do not really understand how carburetors work, but I can take the thing apart, clean out some gunk, and put it all back together again.  I do not need to understand the method of operation very well to complete that task.  It’s still black magic to me.  The carburetor in my mower was covered in all kinds of filth.  The bulb where the gasoline goes before being mixed with air looked like the inside of a forgotten Brita filter.  The jets were clogged with a residue reminiscent of Slimer.  No wonder the mower refused to work.

Less than twenty minutes of time with a 10mm socket, a Torx set, and a can of carburetor cleaner left me with hands that smelled of various petrochemicals, a serious mountain of dirty paper towels, and a mower that fired up on the first try.  I have not touched the inner workings of a small engine since my senior year of high school, which was more than twenty years ago.

I detail this not to beat my chest—okay a little chest beating is in order—but to suggest that the skills and knowledge to repair a lot of the stuff in our lives is well within our reach.  We do not to call someone to repair everything that breaks and we do not need to buy new things every time something breaks.  We bought it, so if we break it we should learn how to repair it.

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