MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MG Y Type - Petrol smell

I can sometimes smell petrol while driving my YB, but I cannot find any sign of a leak under the bonnet. I have checked the fuel line joints and the fuel pump itself.

I renewed all of the seals on the jet a couple of years ago; there is no sign of fuel at the bottom of the jet.

I had a persistent leak from the joint between the float chamber and the carburetter body, which proved difficult to fix. I eventually cured it by smearing both sides of the upper fibre washer with Hylomar Blue.

I have replaced the gasket on the top of the float chamber, and replaced the cut-out fibre washer at the overflow pipe. The float looks OK and the pump cuts out when the chamber is full.

Has anyone any idea of the source of the fuel smell?
M Long

Check the bottom of the carburettor where the choke lever goes in Mike. You may have a small drip leak there and it is just enough currently to drip onto the exhaust pipe and vaporize off. It will only get worse though so deal with it now.

Paul
Paul Barrow

Check the gasket on your fuel filler cap - fuel will spill from here and fumes enter the car via the SWC & boot.

Cheers

Tony
A L SLATTERY

The smell of fuel is a common complaint in older cars and you might ask "why it is so ?".

Modern cars have completely sealed fuel systems - all surplus fuel from the engine is returned to the tank and no vapours are released to the atmosphere.

Our cars on the other hand have open vents on the fuel tank and carburettors, so vapours can be detected easily.

Compounding the problem is the design of modern fuels - to make the fuel more "efficient" it now contains far more aromatics than in the mid-20th century. These aromomatic compounds evaporate at very low temperatures and you will detect the smell of fuel.

Modern fuel actually "boils" or vaporises at 70 degrees celcius - the water in your engine is around 85 degrees, so when you stop moving, the fuel in the carburettors will quickly boil !.

In other words, unless you "de-vent" your fuel system, you will smell fuel now & then even without any obvious fuel leaks.

I hope this helps to understand the problem.

Cheers

Tony
A L SLATTERY

Another thought Mike - how long are your float chamber overflow pipes? They should come all the way from the float chamber over to the back of the front engine plate, be secured to it by a brass P clip and then go down below the bottom of the plate and exit onto the ground. Any shorter and gasoline may splash back onto the exhaust pipe.

Paul
Paul Barrow

I've had this problem too in very hot weather. After a good drive, when I parked the car in the garage, it smelled like gasoline for a few days. Now whenever I arrive inside, I immediately open up the bonnet and put a small fan under the engine so as to help it cool down quickly so as not to let the fuel bowl get to hot in still air. Works for me.
Gilles Bachand

Mike, I too have a petrol smell on my YA. However, I know the problem and as far as I can see its not been mentioned yet. My problem is a small weep from around the sender unit on the right hand side of the tank. I'm hoping that a new gasket and a generous application of Hylomar will sort the problem. First step though is to offload a few gallons of petrol!
Don
PS I am assuming that the YB sender is in the same place as the YA
D G Avery

It is Don.
Paul Barrow

This thread was discussed between 15/04/2018 and 25/06/2018

MG MG Y Type index

This thread is from the archives. Join the live MG MG Y Type BBS now