Ticking fuel pump

[Graham Knight]

Dear All, A while back I overhauled my fuel pump and carbs; new diaphragm etc. in the pump, new washers (soaked in oil as appropriate) and new jets in the carbs. If I switch on the ignition, occasionally the pump races then gradually slows. Eventually it settles to a tick about once a second. Presumably I have fuel leaking from somewhere, but there is no obvious sign of fuel dripping. Should I expect to see an obvious drip at one tick a second? There does not seem to be fuel spilling out from the jets. Just to check, I blanked off the outlet from the pump. Even like that I get about one tick every couple of seconds. Is that normal or have I messed up the overhaul? Thanks in advance. Graham

[DG WHITE]

Attachments :Happened to me too, Graham.  Turned out to be an air leak andthe pump was pumping air !  I always wait until the pump stopsticking, as a fuel leak could be very dangerous.  Had that one toowhen a float sunk in one of the carbs.regardsDave

----Original message---- From : mg-tabc-noreply@yahoogroups.com Date : 25/05/2019 - 16:22 (BST) To : mg-tabc@yahoogroups.com Subject : [mg-tabc] Ticking fuel pump   Dear All, A while back I overhauled my fuel pump and carbs; new diaphragm etc. in the pump, new washers (soaked in oil as appropriate) and new jets in the carbs. If I switch on the ignition, occasionally the pump races then gradually slows. Eventually it settles to a tick about once a second. Presumably I have fuel leaking from somewhere, but there is no obvious sign of fuel dripping. Should I expect to see an obvious drip at one tick a second? There does not seem to be fuel spilling out from the jets. Just to check, I blanked off the outlet from the pump. Even like that I get about one tick every couple of seconds. Is that normal or have I messed up the overhaul? Thanks in advance. Graham

[ian thomson]

As well as sucking air on the inlet side, an uncommon situation, this is most often caused by fuel lacking past the non-,return valves internally.  I have had pumps that do this to no detriment at all though presumably it cuts down the maximum throughput of the pump.  As long as there is no actual fuel leak it can not really be considered dangerous.

Regards

Ian Thomson

Notts UK

[Graham Knight]

Dear All, Thanks to all for the advice. I think it will be worth me checking for air leaks as my car has a rather battered-looking main/reserve tap that is decidedly non-original. That prompts me to ask, would anyone have an original TA/TB main/reserve tap they would be prepared to part with? Graham On 26/05/2019 13:11, ian thomson i.thomson@talk21.com [mg-tabc] wrote:

As well as sucking air on the inlet side, an uncommon situation, this is most often caused by fuel lacking past the non-,return valves internally. I have had pumps that do this to no detriment at all though presumably it cuts down the maximum throughput of the pump. As long as there is no actual fuel leak it can not really be considered dangerous. Regards Ian Thomson Notts UK

[ian thomson]

If you suspect the tap Graham it can be eliminated by removing it and bridging the inlet and outlet pipes to see if the ticking slows down.  On my J2 I made up a crude pipe to do this which can be quickly fitted at the roadside as a get you home measure.  Luckily I have yet to use it.  If you use transparent tubing, perhaps held on by small fuel pipe clips, you can also observe whether there is air in the pipe. Ian Thomson Notts. UK. Ian

On Mon, May 27, 2019 at 10:37 AM +0100, "Graham Knight" graham.knight5@gmail.com> wrote: Dear All, Thanks to all for the advice. I think it will be worth me checking for air leaks as my car has a rather battered-looking main/reserve tap that is decidedly non-original. That prompts me to ask, would anyone have an original TA/TB main/reserve tap they would be prepared to part with? Graham On 26/05/2019 13:11, ian thomson i.thomson@talk21.com [mg-tabc] wrote: As well as sucking air on the inlet side, an uncommon situation, this is most often caused by fuel lacking past the non-,return valves internally.  I have had pumps that do this to no detriment at all though presumably it cuts down the maximum throughput of the pump.  As long as there is no actual fuel leak it can not really be considered dangerous. Regards Ian Thomson Notts UK