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Petrol gauge for 12/4 Harley

Posted: Sat Feb 27, 2021 11:10 pm
by SeanDixon
Have recently taken over the care of a 1933 12/4 in good condition and as far as I can tell so far, fairly original. It was restored some time in the 1990s, registration FW4278. The petrol gauge is of the capillary type and hasn’t worked for years.
While I’d like to keep her as original as possible, I’m tempted to move to an electrical one of the same Smiths type fitted to the slightly later models.
Would anyone know a supplier or have an appropriate petrol gauge gathering dust that they don’t mind parting with? I’ve been watching eBay but no luck so far.
Could potentially restore the original gauge once it’s out but it grates to have anything not working at all.
I have joined the ATDC but can’t yet see the members forums. Thanks for you help. Sean

Re: Petrol gauge for 12/4 Harley

Posted: Sun Feb 28, 2021 10:42 am
by peter_winney
Sean
It would need more than just an electric gauge. You would also need a sender unit in the fuel tank. Maybe even a new fuel tank too to take it - Austin changed the design of the fuel tanks on their cars when they changed over from Hobson telegage to electric fuel gauge. The drain plug and fuel outlet had to me moved to make space for the float to swing on its arm.

An effective electronic solution retaining your old gauge and fuel tank is offered by MP Ltd - 01202 625242. The sender unit float slides up and down instead of swinging.

Open link in new window
https://www.youtube.com/watch?v=GWyb3VMGuz4

Peter W

PS - I have nothing to do with this Co. but they do appear to be enthusiasts

PPS - It works better than the traditional notched offcut of broomstick handle

Re: Petrol gauge for 12/4 Harley

Posted: Sun Feb 28, 2021 9:59 pm
by SeanDixon
Thanks Peter that’s really helpful.
On balance I’d still rather have a gauge and I’m pretty happy sorting out a sender for it but it’s good to know that’s available as a fallback. Hopefully someone will have one.

Re: Petrol gauge for 12/4 Harley

Posted: Mon Mar 01, 2021 7:16 am
by Rod
I thought there were some reconditioning notes for the Hobson gauges in the club technical bulletins if you're keen to have a go at restoring the original system Sean? I know the red fluid is unobtainium [and toxic] but iirc a couple of alternatives were suggested...

Re: Petrol gauge for 12/4 Harley

Posted: Mon Mar 01, 2021 9:29 pm
by SeanDixon
Thanks Rod. I’ve found Tech sheet 5 which covers the fuel gauge and sender and is very helpful. The take home message seems to be to service the sender, replace the capillary tubing and send the gauge away for refurbishment. I was thinking of the electrical gauge/ sender as I can sort that out myself but maybe I should go all out for originality.