23 replies to this topic

[Ethel]

Apart from the split diaphragm scenario, there'll also be a couple of 1 way valves in the pump so it can suck, but not squirt, from the tank & do the opposite to the carb. It's quite possible the seats are a bit tired, especially if they were never intended for ethanol doped juice.

 

You could whip the plugs out so it cranks easier on the starter & rig up some moonshine style plumbing: a good length of hose, or pipe, in to a bottle (at head height, or ideally 8ft). If it'll squirt in to that it can be assumed to be good & if the pipe end is submerged you'd likely spot if there's any back flow.

[Boycie]

To add a bit of closure to this, I removed the tank and inspected it.  It was clean inside, as I thought-

 

 20230128_121849.jpg   36.42K   0 downloads

 

(sorry terrible picture)

 

but after lots of flushing, draining, flushing, shaking, draining etc, I got two items out that I hadn't previously seen -

 

 20230128_120536.jpg   91.57K   0 downloads

 

The black bit was like jelly, it disintergrated as I got it out, but went hard like plastic when out of petrol.  The beige-y coloured ring was still rubbery.

Both are (I think) the 'rubber' rings that go around the fuel level float to stop it rattling at the extreme top or bottom of the tank.

 

Anyway, my theory is that one or both of these was being drawn to the pickup in the tank and obscuring it.  Once the engine (and pump) stopped, the vacuum disappeared and the object drifted away from the pickup pipe.  This wasn't a problem when driving as the fuel sloshes around inside the tank.

 

No problems since.

[bpirie1000]

Well today was a day spent playing with my 9 year project mini. Spent ages scratching head checking fuel pipes yadda yadda.. checked pump not a thing. Whipped that off and a spring went poing....

So...

Turns out that the fuel pump driven off the cam had snapped.. the pumpmarm fell into the sump. Great....just great i thought,.....


Rebuild time again i thought......

So check the pump sooks and blows in the right place....

[Boycie]

Turns out that the fuel pump driven off the cam had snapped.. the pumpmarm fell into the sump. Great....just great i thought,.....
 

 

That's bad luck... and a good reason to ditch the mechanical pump and go electric 

[GraemeC]

Glad you found it - although not rusty flakes, it follows my theory perfectly

[bpirie1000]

Turns out that the fuel pump driven off the cam had snapped.. the pumpmarm fell into the sump. Great....just great i thought,.....

 
That's bad luck... and a good reason to ditch the mechanical pump and go electric 

Would that make it an electric car???

[Ethel]

If you're anticipating some sump fishing, you might get lucky via the  speedo drive cover.

[bpirie1000]

If you're anticipating some sump fishing, you might get lucky via the  speedo drive cover.

Managed to fish it out of the fuel pump hole with the cheap tool my mum bought me for christmas with the bendy grab handle thing that i completly dismissed to the back of a drawer in the garage.....

25 mins of my life i will never get back.....

[Boycie]

Good result