Carb Flooding

[ALAN COCHRANE]

Hi Everyone

I decided to start the car for the first time in a month. While I was waiting for the fuel pump to fill the float chambers I noticed the front one was flooding out the overflow.
I dismantled it suspecting a sticking needle valve but all seemed well. The needle valve and float were replaced only last year as part of a carb rebuild, so shouldn't be the cause. Once I'd put the float chamber back together the car started without any fuss.
I can only assume that the lay up combined with old fuel was the cause of the sticky valve. Has anyone else had this problem?

Cheers

Alan

[Mich7920]

Hi Alan,
I had this and I did exactly the same as you. After some restart I had the same problem.
Happyly the engine was on a jig !
I have recheck the carb leaking and I found that I hadn't the correct spring gap and I think that why the plunger sometimes wedged.
Never leak after.



Mich

[ALAN COCHRANE]

Hi Mich

The spring was set to the right height during the rebuild but I don't see any harm in rechecking it.

Alan

[abowie]

SU float valves will just stick from time to time if left for a while. It doesn't really mean anything unless it happens repeatedly in which case replace it. Often simply tapping the top of the chamber briskly will sort it out.

[christopher storey]

Alan : the real problem is that if the fuel evaporates from the float chamber, the float drops to such a point that the angle between the top of the float and the fork is such that when fuel is introduced, there is so much friction between float and fork and even more so between fork and bottom of needle valve, that the whole apparatus jams.( mainly because the fork is applying more side load than vertical load to the valve ) . A sharp tap on the float chamber with a wooden handled screwdriver will usually cure the problem without the need to dismantle, and you should then be ok unless you let the chamber dry out again

[ALAN COCHRANE]

Thanks for the replies gents.
Not letting the float chamber run dry seems so obvious now. I'll soon be driving the car regularly again so this shouldn't reoccur. In future it seems that I'll need to get into the habit of running the fuel pump regularly over the winter layup. Something I've never thought about before.
Interestingly the GT6 has never suffered from this problem but I suspect that's because during the winter layup I always manually operate the mechanical fuel pump to fill the float chambers before starting. I think this fills them much more gradually than the E-Type's electric pump.

Cheers

Alan