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MG TD TF 1500 - Raw Gas fumes from carba

My TD runs well, but my wife won't drive with me because she says that she smells raw gas on her side of the car (this is a LHD USA model and she is the passenger).

I had new jet seals installed, I have replaced the float bowl gaskets and plugged the holes in the top for the tickler pins.

I do notice a bit of wetness by the front carb, which could be from the carb to intake manifold gasket, not sure. All of the nuts holding the float bowl on are tight.

My questions are:

1. Is it possible to fix this problem? I don't smell it on my side. I have also plugged the holes in the firewall as best I can.

2. What more can I do besides get the carbs rebuilt?

thanks,
Larry Ayres
California
L Ayres

Larry,

You could take off your dampers and look down into the bridge and estimate the height of the fuel in the bridge (the flat part at the bottom of the carb air inlet where the jet rests. The height of the fuel, controlled by the float in the bowl, should be about .16 (a bit more than an eight of an inch) below the level of the bridge, and I use an initial jet setting of about .070 down.

Another idea, which is rare (I've only seen it on my car) is a loose plug on the transverse hole where the float bowl mates to the carburetor body. The transverse hole is what they drilled from the float bowl to the banjo on the float bowl arm. Of course, after they drilled it they had to plug it. Here is a blurry picture of one that leaks.

warmly,
dave


Dave Braun

Likely the wettness is the source of the smell. Where is it coming from? The jet head area/float bowl top or bottom or where?
George Butz

It will go faster without your wife in the car.

Seriously, figure out where the "wetness" on the front carb is coming from and fix it. That will probably cure the aroma. If not then let her drive.
LED DOWNEY

I have been trying to figure out the source for a while. I asked my mechanic to check it out, and he said that he tried tightening the nut holding the float bowl on, which I had done earlier.

Dave, Thanks for your info on the plug and photo. It is all wet around that plug on mine. It is also wet, directly above it going up to the screw holding the dashpots on, also. This is strange as the car has been sitting for a week due to rain. I wouldn't expect fuel to leak from the dashpots. I had the plugs out a few weeks ago, and they weren't showing that it was running rich.

As usual, there may be two problems. How did you fix the plug ? JB Weld ?

It may be time to pull them off and do a rebuild.

thanks,
Larry
L Ayres

Larry, clean/wipe/and dry the carb. Turn the fuel pump on for a minute or so, and find the leak. Otherwise just a guess. The banjo bolt to float chamber lid is a problem spot, that and anything up high will run downward. The fiber washers between the float bowl and the carb body can leak also. You can use a small mirror and a light, as well as your finger to find the leak. George
George Butz

Hey Larry,

LaVerne is right, the leak of the transverse plug is easy to spot if you empty that bowl, allow it to dry, and then power up the fuel pump. If the transverse plug is leaking, it will be the first place fuel shows up. You fix it by tapping it in tight with a small drift (punch) and a hammer.

Notice that my carburetors have the MGA style neoprene gaskets, rather than the normal style. They've always been on my car (well, since 1979) and I think that the previous owner might have thought he was fixing a bad banjo fitting, when all along he had the transverse plug leak. You can notice also that this float bowl arm was broken and repaired, which may have dislodged the transverse plug. For the whole story, look at my website, http://www.dbraun99.com/mgtd15470/ go to Engine XPAG TD2 15613 » Carburetors

warmly,
dave
Dave Braun

errr... George is right too. Sorry George!
Dave Braun

Don't let my wife hear you say that Dave.

I knew I married Miss right. I just din't know her first name was always.
LED DOWNEY

This thread was discussed on 15/02/2009

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