Joined: Aug 2017 Posts: 302 Threads: 54
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Good afternoon all. A problem that has always plagued me has been the dripping carb when the engine is turned off.
In this month's 'Practical Classics' a reader has written in with this problem but only after changing the pump. The solution seems to be a thicker gasket between the pump and crankcase to reduce the stroke.
Has anyone tried this approach and did it work?
Regards from the creative County - Staffordshire
Stuart
Joined: Jan 2019 Posts: 1,481 Threads: 17
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Location: Bala North Wales
Car type: 1933 RP Standard Saloon
07-08-2019, 04:19 PM
(This post was last modified: 07-08-2019, 04:21 PM by David Stepney.)
There has been a comprehensive thread on this earlier. A search on this website should reveal this The replacement pumps are based on the later (and larger capacity) 'U' type pump rather than the earlier 'T' type pump originally fitted to the Seven.
The pump works by the lever running on the camshaft pulling the diaphragm down, sucking fuel from the tank, whilst the return stroke is governed by a spring in the bottom of the pump which sends the fuel to the carburettor.
On the replacement 'U' type pumps, the return spring is considerably stronger than the original 'T' type. An effective cure is to replace the return spring in the replacement pump with that from a 'T' type pump. Fitting a thicker gasket/spacer between the pump and the crankcase will reduce the capacity of the pump but will not affect the delivery pressure, and thus may not be a very effective cure.
Hope this helps.
Joined: Mar 2015 Posts: 5,188 Threads: 223
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Location: Scotchland
My experience and remedy is the same as David describes.
