King-Seeley fuel gauge actually working

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The 35 has been sitting for a couple months now with fuel in the tank and surprised to see the gauge is holding its reading. I’ll probably jinx it bragging about it, but it seems it is possible to get a good seal on the connections. It reacts correctly to adding more gas. I know some have resorted to soldering the fittings, I used Teflon pipe tape so I could take apart if needed.

Maybe I have a different problem, but surprising how long it actually takes for the gauge to come up to the correct reading, I expected minutes with the tiny air hole, I haven’t actually timed it but it seems to be considerably longer.

The new red dye of course went away within a couple months and I never found a solution for that. Its not caused by UV (I tested new fluid exposed for months to the Nevada sun) but apparently a chemical reaction with the copper in the gauge. I read somewhere that the dye originally used was banned for toxicity and  was replaced with something else. I dont know if that is correct. I was going to drop a tiny black Teflon ball on top of the fluid column to make it easier to see but forgot when I was installing the dash.

 

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Hi Jim:  the KS fuel gauge in my ’32 also works, but does creep down after a few months of sitting.  I read somewhere that the system works by trapping bubbles of air in the two upside down cups that are part of the in-tank fuel pickup.

My guage will respond to a short drive with a little sloshing of the fuel in the tank.  But for it to show ‘full’ with a truely full tank, mine is also rather slow to respond.  Maybe 10 miles of driving!!

Greg Long

 

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Greg, yup it is a  bizarre system that relies on the cups getting gas sloshed into them trapping vapor bubbles in the tiny tubes that the weight of fuel in the cup then slowly forces tiny bubbles out under the sending unit, and then the bubbles float up and go through the very tiny hole to recharge the trapped vapor inside the vapor dome. If a perfect seal that system isn’t needed. With all the posts and discussion over the years it seemed near impossible to get a good seal so “just in case” while the car was apart I installed a tiny DC aquarium pump that with a switch under the dash bubbles air under the vapor dome.

There have been many comments about getting the gauge to work for a little while then goes goofy. My theory is that if there is a vapor leak in the line connections to the gauge, then sitting with a full tank of gas will slowly fill the sending unit air tube with liquid fuel to the level of the tank. As the fuel level drops from being driven it takes a long time for that trapped fuel in the sender tube to drop, so then if the tank is refilled within a short period such as during a day’s tour it can end up forcing some fuel slightly above the tank and into the line, and once the tiny air line has  bits of fuel in it, capillary action will screw-up the readings and its all over unless the line is disconnected and back flushed with air.

Not that the electric gas gauges don’t have problems. I’ve chased down problems on two other cars the last couple months, one still unexplainable.

 

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