fuel issue

[johnrip]

My car is drawing fuel into the carbs while it is sitting in storage. The car runs great, but it dripping fuel from the carbs, and there is gasoline in the oil. I assume this is a fuel pump issue. I do not think it is a carb float issue, because the car runs very well. Do you think the pump diagrahm is the cause? Given this, does anyone know where I can get a origianl pump replacement. the reproductions in the USA are terrible, and are not the correct size pump finger. Thanks in advance!

[trsforever]

Hi, I don't have the fuel in the oil problem which should not happen via the pump as there is a drain hole in the base of the pump under the diaphragm so that if it fails the petrol is supposed to run down the outside of the block.
My car is in storage and the problem I had last summer was that the hot weather caused the tank to pressurise and force the fuel to overflow out the carb float bowls onto the floor, its possible to force it up the needles and then it can run down the inlet port and into the cylinder via a open valve it will then leak past the piston rings into the sump.
I would suggest removing the spark plugs and coil lead (so no spark) and cranking the engine to make sure no fuel in the cylinders this will avoid bending a conrod.
I think all the TR pumps I have seen are non repairable, You would be best to get a new pump from one of the recognised suppliers, or remove and blank off the mechanical one and fit an electric one making sure you fit a filter in the line before the pump.
Scott.

[Hasbeen]

Trsforever your tank breather should stop the tank pressuring. I thought NZ had the same US anti pollution system as we in Oz. In that case your tank should breath through the vapour separator, into the charcoal canister. I suggest you check these bits, if you still have them. Any blockage in them could cause the flooding you experienced.

As for your theory of flooding float bowls weeping into the carbs & into the sump, I would think that is correct, & is what is likely. Of course the drain hole in the pump could be blocked, so a split diaphragm could then leak into the sump.

Johnrip the engine can run very nicely with mildly flooding carbs, as the engine can use the fuel at a great rate than the weep, when it is only mild. When a 7 is hard to start when hot it can often be down to the carb flooding after the engine is shut down, due to residual fuel pressure in the line.

I recently overhauled the fuel lift pump in a 1950 Fordson Major tractor. I won't guarantee it, but from memory the replacement diaphragm for it looked to be the same as those in the 7s petrol pump. As the overhaul kit was A$15, & a replacement pump is A$145 here, I'll be buying a kit to check this, if I ever have a pump problem in a 7 again.

Check your fuel pressure. The pumps sold here as replacement can supply up to 4 PSI, & both our SUs, & your Zenith carbs don't like more than 2 PSI. The pump is spaced off the block with phenolic spacers of different thicknesses to reduce the pressure down to the 2 psi required. These are often lost when people muck with their pumps.

Hasbeen