Why is This Gas Cap So Expensive?

A well-engineered, well-manufactured small engine tank closure—at aerospace pricing.

Keeping equipment running in the field has always required a sensible service parts organization. A century ago, automobiles would frequently be laid up for weeks waiting for replacement parts—sometimes for something as common as tires. Today, consumers expect rapid access to maintenance and repair components, and supply chains have evolved to reflect this. Pricing of those replacement parts, however, is another matter. Cost of manufacture is only one component of MRO parts pricing, and the result for consumers is eye-watering cost for relatively simple replacement parts. Jim Anderton describes one example: a simple gas cap.

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Episode Transcript:

If you’re an engineer who likes the outdoors, one thing you definitely understand is that there is a huge amount of high technology in recreational power sports products. Motorcycles, ATVs, jet skis, snowmobiles and outboard motors have seen the same rapid technological development as cars and light trucks, and one of the most beneficial results of this had been the elimination of the time-honored tradition of yanking on a rope until your arm comes out of its socket trying to get a stubborn small engine running.

One motor in my fleet is a small, four-stroke portable outboard, 2.3 horsepower with integral fuel tank, perfect for trolling behind my aluminum car-topper. It’s made by a large Japanese manufacturer who shall remain nameless, for reasons I’m about to describe.

For over a decade, this motor has been reliable—but this summer I’ve had a unique failure: the gas cap.

Now, fuel tank closures on small engines like lawnmowers are little more than a plastic screw cap with a pinhole to allow displacement air in, but on an outboard motor with an integral tank, it’s a little different. This has a switchable vent on top, a simple spring-loaded cam action device that lets air in as the fuel level falls but closes airtight—and more importantly, watertight—when closed. This keeps the dreaded rainwater out and allows the unit to be carried horizontally by its convenient carry handle. 

There are probably 16 or 17 parts in the mechanism, mostly elastomers with a spring and a small stainless-steel washer. This one stopped venting, creating negative pressure in the fuel tank and causing fuel starvation—normally halfway across the lake.

This isn’t a difficult thing to troubleshoot, since loosening the cap resulted in an easy restart and smooth running. So, it was off to my local dealer to purchase a replacement, no big deal.

Until I got the bill: the pretax price for this small replacement part was $92.29.

Let me say that again: this gas cap cost $92.29. Now, I had no idea that the Pentagon was involved in fishing motor parts procurement, and I told the clerk at the parts counter that I didn’t own an F-16. But a double-check confirmed that this is, in fact, the cost of this cap for this tiny outboard.

So why is this thing so expensive? Part of it is the country of origin, which in this case is Japan, and not China where the engine was actually assembled. A factor may be the choice of high-durability polymers, something essential in a motor that spends much of its life outdoors, and it’s a major reason why I prefer to buy OEM replacement parts for outboard motors.

But the real reason why this small part is insanely expensive is because service parts pricing for complex manufactured goods has become disconnected from what it actually costs to manufacture those parts.

What we have here is the consequence of computer-controlled supply chains, where inventory stock levels of replacement parts are tracked by demand, and projected forward, meaning that spark plugs are off the shelf everywhere, and things like connecting rods are special order only.

My outboard has been a good performer, but my previous loyalty to this brand has definitely been eroded by the experience of a 100-dollar gas cap. Now, engineers didn’t set the price of this part, and they did a pretty good job in designing and manufacturing it. But if I turn my back on this brand for my next purchase, it won’t matter that a team of outstanding engineers worked hard to produce a good product. In my mind, this is a $40 or $45 part. But that extra 50-bucks of margin that they clawed out of me last week is something I’m likely going to claw back by buying some other brand of outboard.

Written by

James Anderton

Jim Anderton is the Director of Content for ENGINEERING.com. Mr. Anderton was formerly editor of Canadian Metalworking Magazine and has contributed to a wide range of print and on-line publications, including Design Engineering, Canadian Plastics, Service Station and Garage Management, Autovision, and the National Post. He also brings prior industry experience in quality and part design for a Tier One automotive supplier.