Leaking fuel from SU carburettor, Volvo 244DL 1978

jasonisa

As stated above i have arrived at the oppertunity to purchase a 1978 Volvo 244DL however the car has been sitting in the same spot for five plus years without running, she was "parked up" on the back of a relos property and hasnt even been started, we tried the other day to start the old girl and although she would turn over, she would not fire, we discovered after a bit of rooting around that the fuel pump had died so we replaced with a electric fuel pump, and thought "hey presto car fixed". We turned the key and she kept cranking but although she was getting fuel up she was not firing, it was very soon after this that we noticed the bottom of the carburettor was spitting out some fuel, now although I have worked on various cars all my life, I dont claim to be anything but a backyard mechanic and when it comes to carbys I have no experience whatsoever, could someone please tell me if it is just a seal i need to fix or if there is some other reason the old girl is not firing

Cheers to any help given

jamesinc

It's probably overfuelling and flooding out of the carby. Carby motors have mechanical pumps as the flow rate is pegged to the engine rpm. They run at low pressure. Electric pumps are high pressure and deliver a constant supply, and rely on a return hose to send unused fuel back to the tank.

You'll need to install a working mechanical pump.

@Angus242164 had some good used pumps for sale last time I checked.

Angus242164

There are electric pumps for carby cars that produce low pressure, and bypass excess pressure internally like the mechanical ones do.

If the pump is correct, it may need a new seal kit for the carby.

jasonisa

http://www.goss.com.au/products/GE239

This is the item we installed in the car

Major Ledfoot

If it's a CD Stromberg carb, they have a plastic plug and O-ring in the bottom of the fuel bowl which is often known to fail over time.

Items 22 and 23 in the diagram.
http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=28999#top

The result is raw fuel trickles out of the bottom of the carb.

Orders to Moss Motors take about 7 to 10 days from order to delivery.

egads (she/her)

I think the pressure is meant to be max 3 psi and that pump doesn't start that low, fuel pressure regulator and what bgpzfm142 suggested

Angus242164

I think that pump should be fine, what the pump is doing is filling the float chamber in the carby, once full the float rises up to close the inlet valve, preventing any more fuel from entering the carby.

I'd say a seal or gasket in the float chamber is leaking, the inlet valve may be leaking, or the float might have a hole in it.

A '78 should have an SU HIF6.

jamesinc

Well TIL about electric carby pumps. I agree with everyone else then, next most likely culprit is a perished seal or o-ring.

robv

It will be the needle and seat, stuck or dirty, maybe a hole in the float if it's been sitting for a long time. Remove the bottom of the carbie , you will see the plastic float, if it full of fuel its r.....ted. You will see on one arm of the float it pushes up a little brass valve, remove and clean.
Fuel will only come out if one the o ring on the bottom plastic bung has perished or the needle and seat( brass valve) isn't cutting of the fuel flow. The pump should be fine