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MG Midget and Sprite Technical - Fuel Overflow

Hello Again - I am now ready to fit a HIF 44 single carb to the midget - where do I best route the fuel overflow pipe? I over come the height problem by buying a Howley inlet manifold off eBay for 12.50 a couple of weeks ago - so they are still out there.
P Willoughby

I have just left mine pointing up towards the bonnet

Some have dropped a pipe out through the triangular hole to the outer wing area

I'd rather vent under bonnet where heat will enable any spillage to evaporate than risk it pooling betwen the inner and outer triangle web

but what ever way you deal with it dont just block it off, it supplies atmospheric pressure to the float chamber

As to any danger of fire if it drops on the exhaust pipe lots of cars vented that way with normal twin SUs, out of the float overflow points, I haven't noticed it being a problem

But you need to make these decisions yourself, ask where it vents to with the factory setup
bill sdgpm

The HIF44 on my old Maestro van had a rubber pipe which went to a metal pipe bolted to the block which exited about sump level. I've got the one on my Sprite piped from the carb along the top of the back edge of the inner wing to the space between the footwell side and outer wing. There is a convenient metal cable clip right there to secure it with, but as Bill says, you have to make your own decision as to where you want it to go, I'd hate someone to have a fire because they followed my advice.

Bernie.
b higginson

Mine drops down beside the footwell to vent by the chassis rail.
Dean Smith ('73 RWA)

Anyway to send it back to the tank?
Dave Rhine ('78 1500)

<<<Anyway to send it back to the tank? >>>

That would be a lot of trouble to go to, considering that it may never overflow.
Dave O'Neill 2

sending it back to the tank stops easy float chamber venting

I found running problems with the vent pipe blocked so I imagine a rubber or whatever pipe enclosing the vent might cause the same with the long run back to the tank

it needs to be at atmospheric pressure, it wouldnt take much filler cap sealing to upset the balance

I suspect a drop into the filler neck would serve that purpose if needed though

SO

What Dave says
bill sdgpm

I was worried about the fuel dripping onto a hot exhaust in the (unlikely?) event of the bowl overflowing.

I routed a short pipe into the wheel arch. See attached photos. Its the clear braided hose thats the overflow.


David Banks

and


David Banks

You're right it may never happen, the only cause I can think of is a float needle problem.

David's solution looks very nice & simple.
Dave Rhine ('78 1500)

Best be safe with petrol

but I attended countless fuel leaks on SU equipped cars where the fuel just gushed out of the float chamber top overflow vents as the needle valves wore out or clogged up open

My members were all lucky that hot exhausts just evaporated petrol that dripped on the pipe
bill sdgpm

Thanks once again for the prompt feedback and Dave for the picture - My job for Easter Monday sorted. With the price of fuel going through the roof taking the overflow back to the tank is something we may all need to consider.
P Willoughby

This thread was discussed between 01/04/2010 and 02/04/2010

MG Midget and Sprite Technical index

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