Lister A fuel system problems !

firstly i have had the engine running today fro around half a hour . and notice 2 main problems .

1 , I have leaking fuel unions and tried to tighten them up but they are tight . Its the one on the fuel feed from the pump at the pump end and the carb end as well . What can i do to seal these ? Was thinking on using PTFE tape but is it petrol proof ?

the 2nd is that can a fuel pump pump too much fuel ? As mine seem to be, as much as i fiddle with the carb getting fuel dripping out of the air intake/choke plate its not peeing out but ones its going well you can see it gathering in the bottom hole .

If i was to rebuild the fuel pump / re pack the glands would this help ? The pump does weep a little bit though , how would you repack this ??? anyone who has done it before that can give me some hints ?

regards , matt

Oh and also what size graphite string would i need to use for the packing ?

Try giving the unions a good clean ,they ieak becouse they have been over tightened. Is there not a pipe that runs back to the tank for excesse fuel
Jonesey

JONESEY wrote:Try giving the unions a good clean ,they ieak becouse they have been over tightened. Is there not a pipe that runs back to the tank for excesse fuel
Jonesey

il give the threads and unions a good clean , and Chris there is a return pipe but get fuel dripping out of the choke plate , You can alter the height of the fuel level in the carb though by lowering the return union in the bottom of the carb .

Thats what you got to do then long time since I played with a lister this was the last one
Before and after
Jonesey

That is a Cracking job you have made there mate . Was that engine the one you did for ian ?

reconise it from the dent ....

regards matt

Thats the one Matt runs like a clock
Jonesey

Definitely no problem with PTFE & Petrol.
Can't help with the main problem but carburetor needle valve may be letting by.
Had a similar problem with my Petter A.
Hope this helps,
Phil

Well tonight i quickly wiped off the pump pipes and tank .

I cleaned up all the mating surfaces , and threads with wire wool and the wire wheel . hopefully they should not leak when put them back together . Also stripped the pump apart and inspecting all the parts even though i have taken it apart before , well that was a few months ago .... well a mate of mine did it . I found there is no pump packing

Here are some pictures





Im assuming the pump packing winds around the piston and sits on top of the machined shoulder in the pump body itself , then the spring followed by the piston and the pump cap ....

As well i removed the needle from the carb and there was some much / rust on the tip of the needle so i cleaned that up . Just need to blow through the jet before i assemble it . hopeful all that should cure my problem . I dont think there is any point lowering the level of the return pipe . My theory is that i have never touched it and has not been touched in 40 years and probably not touched from when it was new . All the times i have had it running in the past it has not dribbled out of the carb , so i will jsut put it back together and see . Apparently you are superposed to run the engine half on choke when not on load .

Regards , matt

hi there matt
when i rebuilt my lister A i replace the packing as theere was none left but bits it dripped about 4 egg cups full of fuel a day on the field
i used some***********1/8" -3/16" mine is not a constant diameter lol ********* steam engine gland graphite rope worked well all season no leaks after the first 30 secs of running after standing for a few weeks,
use plenty of good oil while slidding it back in the bore

also remove the fuel start/ run stop screw from top and screw all the way out and check the tip bottom of the needle is complete and not bent
as this couses fuel to drip out through the choker plate
if theres not the problem there
then it could be the inlet valve needs a little more play as people and me have set them back up to the book and find they are worse than before mine spitted small amounts of fuel out the carb and found that the inlet valve was opening just before top dead center and whisping the out out and sucking it back again seconds later

as i learned with mine and others have said later on to me
LISTER As AND Bs ARE A SET BY EAR AND NOT THE BOOK the book will get it going but tweeck later buy sound and you will use less down time and less fuel over the week ends
thanks kev

Kev you are a star mate ! I think you have cured the problem as after i rebuilt it it did not drip fuel and the valve clearances was alot bigger now i have set it to 10 thou inlet and 12 thou exhaust as i have stripped it down again for another cleaning .... and it makes sense to me .... i think its going to be one of those tricks that not many people will know as on another forum no one has even suggested that idea yet ....

the needle i have removed and cleaned its not visibility bent or miss shaped but where its been stuck in same position for 40 years is a slight dint in the needle just before the shoulder when goes parallel so not on the tip .Dont think that would effect it .

Cheers mate .

Matt

Oh kev could you measure your inlet clearance mate , would save me alot of time going by a bit at a time . I can go by what yours is set and tweek from there .

Cheers .

Matt

[quote="matt86_wd2"]Oh kev could you measure your inlet clearance mate , would save me alot of time going by a bit at a time . I can go by what yours is set and tweek from there .

Cheers .

Matt[/quote


matt give me ten mis to go back and dig the engine out and measure it up for you and ive put the packing diametre on above now for you
back soon as
kev

hi there matt
inlet on mine is 0.25 thou
exhurst is 0.27 thou
we all forget that these engines are near a 100 yrs old as there new to us LOL in the 60s and is classed as a fine and solid internal state by the anson engine muesum men that did a rally field parsal stripe down demo with mine
so the wear and tear has to be allowed for mine was rebuilt buy lister
so it looks like the 2 thou difference is working still lol
hope this works for you like it for me on mine
let me now how she goes after
thanks kev

[quote="kevjhnsn"]

matt86_wd2 wrote:Oh kev could you measure your inlet clearance mate , would save me alot of time going by a bit at a time . I can go by what yours is set and tweek from there .

Cheers .

Matt[/quote


matt give me ten mis to go back and dig the engine out and measure it up for you and ive put the packing diametre on above now for you
back soon as
kev

At this hour mate , your a keen enthusiast