Fuel leak onto exhaust manifold - Help!

[James_B]

Hi all,

I'm new to Healeys having bought my first car, a 3000 Mk1, a few weeks ago.

It is one of the cars with the electronically operated auxilliary enrichment carburetor that was discontinued.

While tweaking the main carbs this afternoon I noticed that, while idling, periodically significant amounts of neat fuel were being 'blown' out of the air intake straight onto the exhaust manifold. I'd estimate 10ml of fuel would pour out each time and it would reoccur every 2 minutes or so.

The unit is no longer activated by water temperature, rather a switch on the dash. The choke was off at the time.

I'm now very nervous to drive the car but have no idea where to start. If any one has any experience of this issue I'd be most grateful for any guidance.

Many thanks,

James

 

[Keoke]

Set the electric choke back up like it is designed to be. Sounds like it is runing too rich.

 

[James_B]

Thanks for the advice. I'll probably do that in due course but given that it is a switched device I'm pretty sure it won't make any difference to the fuelling issue?

You are correct about the richness - you need to run the car extremely rich for it to drive anywhere near properly, the downside is that hot idle is dreadful with iut constantly trying to quit. I set the timing and tuned the carbs down to about 4% CO (the lowest I achieve before running out of adjustment). The idle was then lovely but the car became virtually undriveable due to misfires below 2500rpm - I had to drive it like a racing car to get anywhere!

It was when i put it back to how I found it that i noticed the fuel leak. My guess is that the solenoid is not closing the system fully and allowing the thermocarb to pass fuel into the induction manifold. That said I'm not sure that would explain why the car misfires when tuned "properly"...

 

[James_B]

Having stripped the carbs I've discovered that it was a sticky float valve in the rear carb. The thermocarb's intake is lower than the float chamber overspill surprisingly.