Hi All,

I am looking to get a new/spare fuel pump and can't seem to find one which will suit my mini:
Fuel tanks are 5/16" outlet
Link pipe is 5/16"
Hardline from pump to the carb under the shell is 1/4"

Is this an unusual setup? I can only find fuel pumps with 2 x 5/16" ports (or ones that are 8mm). Or do you just cram a 1/4" rubber hose onto the 5/16" port on the pump?

My 850 parts book says:
Pipe from tank to pump is 21A207 (quoted online as 5/16")
Pipe from pump to hardline is 21A208 (quoted online as 5/16")
Hardline is 21A919 (quoted online as 1/4")

Cheers

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Tim, I suppose I should answer this since my 850 book is a little obscure with regard to the part number shown (it being the drawing number which covers both 21A207 and 21A208). The rubber hoses all have 1/4" internal diameter. 21A919 is 1/4" bundy tube. However, as you've noted, the pipe connections at the fuel pump and tank are 5/16 OD (but you will be pleased to know that the internal diameter of these pipes is 1/4") and so it would seem that yes, you push the 1/4" ID rubber hose over the 5/16" pipe (which has an additional swage which bumps it up a little over 5/16"). regards, Tony

Thanks Tony. I’d been looking at HYL2980 and Somerford Mini sites (which had the same part number flexible hoses listed as 5/16”)
https://www.somerfordmini.co.uk/fuel-sy ... ctric-pump

I notice in your book that the flexible lines are listed as 15/64” ID which is one size smaller than 1/4”?

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My mistake. I took a liberty of saying 1/4" ID. The actual value is 0.225 – 0.240” ID . I think I took the average of these and wrote 15/64. .

I use 1/4 pipe, heated in kettle hot water they then slip onto the 5/16 outlets pretty easily. You will have to cut them off however as they stay tight

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Cheers Dave.

Tim
On my van I am using a su electric pump
Tank to plastic filter that has 1/4 and 5/16 spouts , 1/4 hose (5/16 on sedan )
Filter to pump 5/16
Pump to Adaptor 5/16
Adaptor to body hard line 1/4
Cant remember where I bought the adaptor from Sorry

I agree that the Somerford Mini catalogue is confusing by specifying 5/16, but the drawing definitely shows 0.225 – 0.240” ID and 0.5" OD (for the rubber hose component). The rubber hose is of course covered with a metal braid, terminated on each end by a rubber cap, and also fitted is a rubber sleeve part way along. The presence of the metal braid makes it very difficult to cut the pipe off unless it is peeled back which is not so easy to do on a short hose. The braided hoses from Minisport all show 1/4" ID.

Thanks All

I'll try fitting a 1/4" hose over the pump outlet and see how that goes

Otherwise I can see some adapters like this
https://autobarn.com.au/ab/Autobarn-Cat ... oductIndex

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The hose I use is the fuel injection type with the matching clamps. Heated in boiling ish water go on fairly easily.

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Cheers Dave.

I always use 1/4" hose unless a filter is being installed which has both sizes.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I use gates or dayco US made 1/4 fuel line it's rated for unleaded fuel and doesn't harden with use unlike cheap stuff.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I run SU pumps AUF214 in all my minis. I only faced this issue when I discovered the tank lines were 5/16" and the rest of the car was 1/4". The pump outlet to 1/4" hose is the tightest fit but I don't expect you'll have any problems.
Have always had the suspicion that the little plastic spouts are deliberately made to be just under 5/16" and just over 1/4" to satisfy all options!

I run a copy Facet red top pump with 5/16" inlet fitting (from the tank) and 1/4" outlet fitting (for the hard line to the engine bay).