Carburation

[peterg]

No the diaphragms are good.

I did change the fuel filter today as it had some crud in it. No improvement.
Final check. Undid the union, turned the fuel tap on. Nothing. As the fuel gauge reads half full and is probably correct the fuel fuel line is blocked.

Makes sense. But how to clear it? It's a long way from the fuel tank to the isolation tap.

[flyinghorse1]

Peter,
You really have to drop the tank & sort out why crap is getting through.

I have had this as a student in a Hillman hunter and used to carry a foot pump to pump the crap back to the tank from the engine side . However it always returned.

I also have a vintage Swift that did this-and cut out like you said. The motion must be mobilizing fines & clogging the line.

You may get lucky by draining the tank & starting afresh.

Frost do a slosh kit that should fix the issue if you get the tank out--I have used it in my Swift & a friend in an AC Ace and it works.

POR-15 Car Tank Repair Kit | Frost Auto Restoration Techniques

Graham

[Geoff Dowdle]

peterg,
What model Bristol are you working on ????
If it is a 403 (AB2 engine as you advised) the bottom of the tank has probably got a lot of corrosion in it and might need replacing .

The fuel lines often get squashed where they go under the chassis , just forward of the LH rear wheel area . Foreign matter can get blocked in this restriction.

If you want to fix the problem properly I suggest you inspect for leaks , remove the tank , initially clean & inspect it internally , if a alloy 401/3 check for corrosion holes , replace the fuel line & filter (I assume you have a proper disposable filter between pump & carbs).

You should then have a clean fuel system to the carbs which will be a good position to then start a correct tune up.

Geoff

[peterg]

Got to the tank today and there is a layer of sediment at the bottom that wasn't there two years ago and a partial block on the elbow into the tank.

Cleaned the blockage up and the engine is running. So well that it doesn't stop when the ignition is turned off! Another new one on me.

I will need to rig up a fuel filter in the boot as mine is in the engine compartment and there is plenty to clean out.

Can't get the fuel gauge to operate. It either reads as full, empty or just over half full depending upon where it is wired in.

[peterg]

Replaced the small filter before the pump and fitted a large VW filter in the boot. Put in some new petrol and a bottle of Forte petrol treatment

After a false start I took the plunge and drove the car home. Took about three hours to cover 45 miles. The car broke down thirteen times! Twelve for fuel blockages and finally an electrical problem. On the tenth breakdown (Boxhill dual carriageway) I put the left side of the car onto the verge. At that angle the petrol washed down to the side of the tank leaving the pick up pipe high and dry. I decided to push the car back onto the carriageway and about 100 yards down the road to a side road & safety where I found the pipe was submersed again so I carried on to the roundabout and filled up, only to breakdown again just out of the petrol station!

I'm getting quite a taste for petrol! Blowing seems to clear the pipe better than sucking and avoids the inevitable mouthful. However, it does mean that the sludge has still to be sucked up at some point rather than be trapped in the fuel filter.

Took the car back on Saturday and it only failed three times. So I feel that a lot of progress has been made. Think I will replace the filters when I next go down to see the car.

When it has enough fuel it goes well except for a lot of explosions in the exhaust at small throttle openings. Tickover is 1,000 rising to 1,500 rpm when hot.