Carb help pleeeeeaaassse!

[Surferjoe]

Hi all.

Firstly. No nothing really about carbs, especially SU's.

The car was running well. No problems and then suddenly started missing. I thought it was electrical until I found fuel pumping out of the both carb overflow pipes.

I thought it a bit odd for 2 mechanical issues at the same time but swapped them for another set I had.

Car runs ok then starts missing and running lumpy. Fuel starts to come out the overflow and then it dies.

Won't restart for an hour and then the same process. If something in the carb is stuck what are the odds of all 4 carbs?

Help please.

[Tamworthbay]

Hi all.

Firstly. No nothing really about carbs, especially SU's.

The car was running well. No problems and then suddenly started missing. I thought it was electrical until I found fuel pumping out of the both carb overflow pipes.

I thought it a bit odd for 2 mechanical issues at the same time but swapped them for another set I had.

Car runs ok then starts missing and running lumpy. Fuel starts to come out the overflow and then it dies.

Won't restart for an hour and then the same process. If something in the carb is stuck what are the odds of all 4 carbs?

Help please.

Odds are small but better to check thoroughly, the fuel level is controlled by needle valves and they can be problematic bit four at once? Google SU needle valve and you will see what you are looking at. A simple way to check they are operating ok is to lift the float and blow down the inlet, it shouldn't let air through, let the float go and air will flow. Then check the float levels are ok.

As its all four playing up it could suggest over pressure on the supply. What fuel pump do you have? If it's a mechanical one then it would be very surprising (impossible?) for that to be the case. Universal electric pumps can be funny things.

So more info needed and a couple of things to check. Don't be afraid of SUs, they are beautifully simple things really.

[Mahesh]

I'd put the previous set back on, and take off the float chamber lids, remove floats, and the nut and seat valve and clean out.

Also check the fuel pipes for flaking.

There are some pics on the forum, but a quick and easy job, if that's all that's wrong.

[Surferjoe]

Thanks all for your advice. I will have a go at cleaning the carbs I took off and then refit them.

It's metal fuel line up to the filter I fitted in just in front the carb and it's a standard mechanical pump.

[Jon Tilson]

Your fule line will have some rubber sections that I suspect are perishing internally due to the increased use of bio ethanol in most
fuel these days.

I hear that Esso is better than Shell, but have no real evidence to support that, plus no guarantees who delivers what these days.

Your best bet is to clean out your original carb float chambers and then go through your fuel line and change all the rubber joiners for
new spec fuel line.

Then get a cheap in line fuel filter and have it just down stream from the pump. The rubber flakes wont help your pump valves much either.

Blocked float valves will cause flooding and over rich mixture. Once you have sorted this your car will be back to normal.

Jonners