Herald solex accelerator pump

[Matthew Holland]

The diaphragm is fine, the non-return valves are present, in fact I can see and hear the pump mechanism working just fine.

It’s just that there is no fuel getting to the pump from the float chamber. 
 

Can anyone tell me how it gets there and how to check for blockages?

 

Thanks!

[Pete Lewis]

there is normally a small plasic ball and spring to make a non return valve under the pump tube ,item 38

[Matthew Holland]

Yep. Got that. 
My problem is there is a blockage between the float chamber and the pump itself. 
 

I’m beginning to think I need to get something acidic to pour into it/soak to clear the blockage. 

[Pete Lewis]

pepsi or vinegar often work well .there could be corrosion in the drillings if its been unused for a few years the stuff grows 

Pete

[Matthew Holland]

Am trying vinegar in my ultrasonic cleaner as I type. 👍

[Clive]

Not a help here as the carb is off the car, but years ago when my dear Dad bought a "bargain" herald (ha ruddy ha) and dumped it in my garden when I was on holiday...

 

Anyway, me prepared to strip the carb etc, but dad gets me to start the engine rev the nuts off it and then he blocked the carb intake with his hand. Car stalled, repeated a couple of times, and eventually the carb behaved. I guess the suction cleared the jets etc nicely, may work on the pump too?? Also show that old skool tricks are sometimes quite handy....

 

Ultrasonic is about the only way of clearing those passages if properly blocked. Carb cleaner squirted down passages and an airline can also do the trick, it a tad violent.

[Colin Lindsay]

Boiling it in washing powder does very little, so one more old wives garage-tip debunked... maybe I should have tried a full 60 degree wash cycle but for some reason, 'er indoors wouldn't let me.

 

[Matthew Holland]

Well, I’m happy to say the vinegar (specifically Morrison’s 90p malt vinegar) plus a judicious amount of mouth to mouth from myself fixed things up perfectly. 
 

It turns out that in addition to the non return valve beneath the jet itself and the one way valve under the brass screw above the pump diaphragm housing, there is ANOTHER non return valve somewhere inside the carb that had become stuck. 
 

That’s a part I cannot see listed in the exploded diagram. It’s definitely there though. 
 

👍