Morris Minor Owners Club

My Minor has previously been converted to negative earth and has a Facet electronic fuel pump fitted, I was thinking of getting an original SU electric pump as a back up because they're serviceable unlike the electronic one.
Can the original SU type be run on negative earth or would I have to convert back to positive earth to use it?
Thanks.
Neil.

The original pump works with both positive and negative earth.

Modern SU fuel pumps are indeed dual polarity

You say "modern" SU fuel pumps are dual polarity, does that mean 1960's originals are not?

If I remember correctly (I could be wrong) SU sold positive and negative pumps at one time but for many years they have been dual

The ONLY pumps that are polarity sensitive are the electronic ones. Original SU pumps (still available new today) will run in either direction without problems, although, it may be wise to change the points if you reverse the polarity of an already used pump, however, I never have and have not had any problems.....

http://www.sucarb.co.uk/TechnicalDetail.aspx?id=49

Note the reference to polarity

Single type electric pump (Standard on a Minor) http://www.sucarb.co.uk/TechnicalDetail.aspx?id=53 is not polarity sensitive. Other pumps (dual type) as per your link may well be, but not used on a Minor....

An old pump will be fine on -ve earth. Clean or renew the points - and try it out before carrying it as your spare. In fact - I would fit it - and carry the 'foreigner' as the spare!