Fuel Overflow at back float valve

[jackathy]

A perfect day to drive here in CT and I can watch all the Bristish cars going to Lime Rock for the races. I've heard MG's are going out on the track during the lunch break today.

But, my sprite will only drive for about 5 minutes before fuel flows out of the overflow of the back Float. I've replaced both float valves. The back float clearance seems to be at the max of 3/16, but it is plastic and there doesn't seem to be a way of adjusting it.

What should I be looking at now? There is a similar thread over on the the Healey forum, but nothing seems to answer my problem. My mechanic says it wouldn't be the fuel pump, but what else could it be now?

Thanks,

 

[spritenut]

Dirt in the float needle/seat or out of adjustment.
On the plastic floats you have to shim the seat with a washer to get it correct or at least to get it to stop leaking.
There was a batch of wrong made float seats about a year ago.
Milled wrong and the needles were way off.
You have to compare the old with the new to see the difference. I went nuts with leaky floats on my 58 over the winter. Bad valves.

 

[jackathy]

Thanks for your reply. It has what I think is a plastic regulator before the first float valve. I put on new fuel lines this afternoon and left the regulator off. I made it to the end of the street before the pump starting clicking as if I was out of fuel. I was spitting out fuel from the overflow.

I'll compare the old to the new tomorrow and maybe even adjust and put in the old to see if that might solve the problem. The front one leaked until I replaced it, then the back one leaked and I replaced that.