8 replies to this topic

[maystro]

Hi guy's,

 

I have a Mini Moke where I installed a new SU fuel pump in the cabin area on the firewall. 

I had a Facet which seemed to be too powerful because fuel would start come out of the overflow on my HS4 carby if I had the ignition on and not have the engine running.  I know that could have been a float needle problem?  

 

Well now I have a brand new HS4 carby and a brand new SU fuel pump and it was pumping away when I was checking all the new fuel lines.  I have a fuel filter in the fuel tank area pre pump and another glass filter in the engine compartment just before the carby, both were half full.

When I finally went to crank my motor over, no go.  I noticed the fuel filter in the engine bay had some dirt in it and it was empty. The fuel pump doesn't even make a noise now.  

Sorry for the long winded question but could dirt kill a new SU fuel pump and is their a cure?

 

Thanks Brad

 

 

[nicklouse]

I would have just fitted a pressure regulator.

 

but back to the new pump. Check the wiring. Check that it works directly connected to the battery.
 

[maystro]

Thanks Nick

 

I was thinking their was a problem with the earth so I put a spanner from the earth terminal on the pump body with a spanner to a different screw on the body of my Moke  and got a  shock so I am guessing it is getting power.  

Is this a right assumption?

I know Facet pumps made a lot of noise which didn't really bother me, at least you knew they were working.   

Do SU pumps make some kind of noise so you know they are working?

 

Brad

[gazza82]

 

Thanks Nick

 

I was thinking their was a problem with the earth so I put a spanner from the earth terminal on the pump body with a spanner to a different screw on the body of my Moke  and got a  shock so I am guessing it is getting power.  

Is this a right assumption?

I know Facet pumps made a lot of noise which didn't really bother me, at least you knew they were working.   

Do SU pumps make some kind of noise so you know they are working?

 

Brad

They tick quietly when pumping but not continuously. Was always hard to tell if the SU on our Midget was pumping but a tap from a screw driver handle usually got it going.

 

The shock from the earth doesn't sound right .. ?

 

Edited by gazza82, 07 August 2020 - 01:20 PM.

[sonscar]

[u]SU pumps I am familiar with tick whilst pumping and stop pumping when the outlet pipe is under pressure,they tend to not suck very well and are usually near the tank..If left standing for a while the points can stick and stop it working,the pump occasionally needs adjusting,a trial and error process.But mainly they just work.Steve..

Edited by sonscar, 07 August 2020 - 06:24 PM.

[Spider]

Hey Brad,

 

As has been suggested, check there's power to the Pump first. They have a bit of a current draw, so the connections need to be tight and clean.

 

I see you've fitted a Filter on the suction side. I'd suggest removing that and perhaps fitting it to the Outlet side. Fitting a Filter on the Inlet side of any Diaphragm Electric Pump can cause them to stall in an energised state when the filter blocks up. The Coils in these are only short time rated as so t causes them to burn out. There is a possibility, that this is what may have happened, though, given the filter is new, it's not likely. Likewise though, check the suction pipe is clear and not blocked (kinked etc) or it can do the same.

 

They don't 'pump' continuously like the Facet does. It only 'pumps' as the fuel flows from the outlet. The Pump draws down on the Diaphragm inside it and it has a Spring that pushes the Diaphragm back (and sets the output pressure), when the Diaphragm reaches a certain point, close to it's resting position, it trips the internal switch (and even the electronic ones have a switch) and resets the switch once it reaches full stroke. Then cycles over again, as the fule volume in the Diaphragm chamber of the pump reduces.

 

Best way to check if it is working is to take the fuel hose off the Carb, turn the key and see if you have fuel flow. Best to put the hose in a container and be mindful of sparks etc when doing this.

[maystro]

Hi Spider, I did what you said and took the fuel line off the carby and low and behold fuel started pumping out every where and the pump made a slight ticking noise.
I have to get use to how quiet these pumps are as opposed to the old thumper facet one I had.
Anyway I connected the fuel line to the carby and I finally have lift off ?
I'm guessing maybe it was an air lock or something.
Anyway happy days, now for some road testing. I 3 different needles I want to try.

Thanks guys.

[Spider]

Result !

 

Good work, Onwards and upwards

[cal844]

Glad it's fixed