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MG MGB Technical - Carb overflow

Had an overflow from my carbs which I have sorted, but I noticed that the pipes are clipped to the engine block right in front of the exhaust. This seems highly dangerous. Where is the best to route them; I am thinking of taking them to the front of the engine and clipping them to the steering rack. Any thoughts?
R E Merrall

Never known there to be a problem if they are clipped where they're supposed to be, i.e. by the front engine mount. For your peace of mind just extend them, out of the way, with some rubber fuel pipe.
Allan Reeling

Surely if petrol overflows it would blow back onto the exhaust with consequent risk of fire
R E Merrall

As mentioned above, if the overflow lines are installed in the proper spot very close to the front motor mount, the lines will allow any excess fuel to fall onto the ground and not reach the exhaust manifold. That's the whole purpose of their design. Yours may have been modified and are too short to accomplish this. RAY
rjm RAY

Thanks for the advice; I'll have another look.
R E Merrall

Rod, the pictures on this website may help.,3067274

Andy Robinson

My roadster came to me with them attached to the chassis side of the rubber mount, which means the very short bit of hose between the carb port and the overflow pipe is being flexed every time the engine moves. Being such a short piece the risk of rupture is high, so make sure they are attached to the engine side. Early cars did have them attached to that mechanical fuel pump blanking plate bolt, later on they may have used the hole in the engine restraint bracket that fits round the left-hand mount.
Paul Hunt

Thanks for the pictures. I still think the overflow could blow back onto the exhaust so I might make the pipes a bit longer.
R E Merrall

I terminated my pipes just above the oil sump/engine block flange. I didn't want the pipes exposed to the slip stream at road speed as the draft effect could pull a slight vacuum on the float bowls.

My car didn't have the pipes when I bought it. Finally I searched the internet and forums for routing examples and fabricated them after making 12 gauge wire templates. After a bit of fine tuning they work fine. They clamp to the engine at the rear fuel pump blanking flange bolt. I used the Moss clamp and it worked fine. A simple tubing bender helped make neat looking bends.
Robert McCoy

I did exactly as Robert did. I used brake line tubing and bent it by hand following a wire template.

I guess there is always a risk of fire - install an extinguisher in the cockpit just in case.

I did have an episode where I found a big pool of fuel on the garage floor after I drove out onto the drive. After that I fitted an inline glass fuel filter, just to try and prevent any crud getting to the fuel bowl from stopping the seals from sealing. So far so good (touch wood)
John Minchin

Thanks for the advice; I have also terminated the pipes just above the sump level.
R E Merrall

This thread was discussed between 01/01/2016 and 12/01/2016

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