Gasoline politics and Seafoam
There’s hardly anything luckier than running into a certifiable genius when you can’t figure out a problem. I’d just bumped into a friend of mine at the lumberyard, and I was pickin’ his brain like meat from a crab-leg.
One of his many talents is a deep, engineering-level knowledge of everything automotive. For example, he kept all the old cop cars running safely for the stunt scenes in the “Blues Brothers” movie remake. He was a motor consultant to “Batman Begins”. He knows all about fuel chemistry, all the way from the crude oil entering the refinery cracking tower to the deposits inside your car’s tailpipe. So he was just the guy to ask about the fuel problem in my VW. It turns out the problem is political…
Oil companies in the US have been unwilling to comply with environmental rules (because they’d have to charge an extra dime for their incredibly cheap gas) so they have not been building any new refineries. Instead, they just cranked the old ones up to maximum capacity, so they have less control over the purity of what comes out each level of the towers. This situation was not improved by the hurricanes that damaged the gulf coast last year, by the way.
It had not occurred to me to blame the fuel itself. The gas you’re buying? Well, it’s approximately what it’s supposed to be, but it varies a lot. They don’t have time for recracking when the tolerances are ‘off’. Usually, this is fine. The computer in your car can compensate and you generally don’t know about it.
But suppose your car ain’t got one o’ them thar computer dealies? Suppose it was built when gas refineries were run as if the purity of the gas mattered, because cars had carburetors… say in about 1967? And suppose it’s an air-cooled engine that runs thirty degrees hotter than the one in your car? The fuel sits in the float bowl, getting nearly to boiling temperature. Then it gets sucked down a little tube, through a tiny jet, and that’s where the impurities crystalize into ‘lacquer’.
This aligned neatly with my experience. I’d take the carb out, thoroughly clean it with very agressive solvents, and the car would run great for about a day until the idle jet and idle trim jet (which are really the most important ones up to about 2300 RPM) would clog up. My first thought was ‘plain old crud’, but my gas tank was fully reconditioned, there’s a fine brass screen, and two fuel filters inline before the carburator. That should have caught any POC.
When this happens, I know it. The car loses power at low RPM’s, it runs even hotter than normal, and it bucks and kicks. It will idle either at high RPM’s or not at all. It’s embarrassing, not to mention uneconomical, polluting, and unsafe. It’s very bad for the engine itself.
I had tried various fuel system cleaners to dissolve the lacquer, but to no avail. My friend recommended something called ‘Seafoam’, which is an old product that I would not have thought to use. He said to start with 30% higher-than-recommended concentration, and to be prepared to swap out the fuel filters a week later (after all, despite the clean tank, the fuel line is 39 years old). Then, use when needed at normal concentration.
It worked. I spent the last few days hotrodding around town on various errands and the car idled and performed exactly the way it is supposed to. In fact, as it never has since I built that engine. Yea, Seafoam!
UPDATE: I have consolidated this post and all the other fuel and carburetion related posts into one: 34PICT-3 Carburetor Final. That post will also be updated when new information comes in.