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Post by ctdahle on Mar 25, 2006 15:04:43 GMT -7
I've got a Sonic Tronics Mark V fuel pump. I've had it for years. It works fine the first time I use it each day. But by the third tank, it stops pumping although the motor still turns.
I figured maybe there was a problem with the drive coupling, but when I open the case it works fine.
I know, I know, I should just buy a new one. They are cheap enough, but I hate to give up.
Anyone have any ideas?
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Post by ctdahle on Mar 25, 2006 18:10:01 GMT -7
So I took it apart again.
The maddening part of the problem was that I could not duplicate the failure when I had the bottom of the case off.
Inside the case there is a small electric motor, the kind in a gold colored metal case that you can buy at radio shack for a couple of bucks, and a small nylon shelled centrifugal pump with a metal shaft. The coupling between the motor and the pump shaft is a piece of black rubber tubing with a pair of spring clips at each end.
When the pump first starts running everything works fine, but there is a leak in the pump seal and fuel drips out. It collects in a well in the bottom half of the case, and once the well is full, the coupling sits in a nice bath of glow fuel. The fuel then wicks into the coupling and it begins to slip. A partial solution would be to drill a drain hole in the bottom of the case so that the fuel would not collect, but I decided to remove the bottom case half entirely instead.
I secured the innards in the remaining case half with tie wraps. Then I relocate the pump in my flight box so that any fuel leaks down and away from the coupling and motor.
The coupling is now accessible so that I can wipe it down with a rag if it begins to slip, but I tested it out and was able to fill and drain the tank three times in quick succession before there was a problem.
Obviously I need to replace the pump because the seal is not replacable, but this fix should tide me over until I decide which pump to buy.
Have any of you tried the new Sullivan pumps?
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Post by Grug - American Neanderthal on Mar 26, 2006 12:03:07 GMT -7
I have an Sonic Tronics MK V that quit me years ago. I have quit using the powered type ones, becasue iot never failrd the battery would be dead. Instead I have used geared type crank pumps and been happy with them.
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Post by ctdahle on Mar 29, 2006 21:16:05 GMT -7
I don't know why I think I have to have an electric pump, I'm such a Luddite about everything else...
I guess it's just that since I have a flight box that delights me and I have so carefully wired it all up, I hate to abandon the nifty switches and buttons.
Anyway, now that I have reoriented the pump, it seems to be working just fine. It sprays a bit of fuel, but the coupling doesn't seem to have any tendency to slip anymore.
For a fuel bottle I use a liquid detergent bottle. It has a very large cap. Since the fuel pump actually still works pretty well, I'm thinking of modifying the cap to contain the leakey pump head inside the bottle and isolate the pump motor and wiring outside.
Slimline sells a pump that is integrated into a fuel bottle cap, but they want about 80 bucks for it, which is about 70 more than I am willing to pay. Anyway, it's more fun to tinker than to buy.
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Post by Grug - American Neanderthal on Mar 30, 2006 18:26:38 GMT -7
Heh, I know. I have a power panel and everything, and then never charge the battery, have taken it out in fact because I dont like all the wires hanging off the box. Besides it weighed about 60 lbs and I welcomed the weight reduction of the dry cell.
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Post by 50PlusAirYears on Jan 5, 2007 17:04:22 GMT -7
My sonictronics quit after about 15 years. Motor failed. I replaced it about 3 years ago with a Hobbico.
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Post by JimCasey on Jan 10, 2007 4:22:08 GMT -7
Pay up your fire insurance. That's a brush-type motor and it makes sparks. And you're dripping methanol on it. I trust I do not need to review basic chemistry...
Eric is right. The crank-type pumps are good. The only one I have had to replace was damaged in transit-I had it bolted to the outside of my flight box and it got hit on the handle.
I like that I can count cranks to measure how much fuel I am putting in/taking out.
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Post by ctdahle on Jan 10, 2007 20:14:17 GMT -7
Pay up your fire insurance. That's a brush-type motor and it makes sparks. And you're dripping methanol on it. I trust I do not need to review basic chemistry... The thing is Jim, I've owned or at least messed with a half a dozen electric fuel pumps over the past 30 years and most every one of them ended up drenched in glow fuel at one time or another. It's been 9 months since I started this thread and the pump has been running, pretty much soaked in fuel, ever since. I don't know why they don't go up in smoke and flames, but this one sure hasn't, and I don't think it's because I'm just lucky. Of the several I've taken apart, I can't say that I've noticed there is much inside of them to prevent glow fuel from drenching not only the motor, but the switches, brushes, and commutator too. Nothing special about the motors that I can see either. They are stock "toy" motors with quite visible cooling perforations in the case and brushes hanging out in reasonably plain sight.
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rory
New arrival
Posts: 5
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Post by rory on Dec 9, 2008 2:13:38 GMT -7
Yes. I had a Jetta that did the same thing. When it gets hot listen for a buzz coming from near the gas tank. Sometimes they put 2 fuel pumps in. One in the tank, and one near the motor. bakersfield limo service
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