'77 ADFA carb leaking into secondary at idle

[Rupesy]

I am having problems getting the car started recently and noticed a lot of black smoke while trying to start. I pulled the air cleaner and noticed fuel dripping from the secondary during idle. I think I had this problem before with my float bowl, but bought a new one, new valve and readjusted. I looked at it today and it seems like it is still adjusted properly. Any suggestions?

[Rupesy]

Well I pulled the top off the carb and checked the float again. I adjusted it slightly, but then decided to have a look at the needle valve. I think it may had something stuck to it, but not really sure. I cleaned it off, but did notice the rubber had deteriorated slightly and was wondering if that is one of the symptoms of ethanol. Anyway, got it all back together and now runs great. I think I'll order another needle valve to be sure. Wish I could of had a more definitive problem. Anyway, noticed black smoke coming from the engine bay on the exhaust side. Found the the manifold to pipe connection with massive leak blowing hot air towards the radiator and the firewall......

[Rupesy]

This continues to repeat itself every other month. Yesterday I couldn't get it started. Pulled the air cleaner off and noticed fuef puddled up ont the secondary again. Dumped it and tried to start again. Fuel just started dumping into the secondary and it continued for a little while even after cranking stopped. I just took the top of the carb off and looked at the float. It seemed like it was out of adjustment so I eyed it up and bend it down so it wasn't close to the top. That seemed to do the trick again. The float is brass and kind of flimsy, but didn't think there was enough pressure in the bowl to cause it to bend over time. Is it the fact that I am adjust ing the float that is stopping this issue or am I breaking some kind of vaccum lock when I pull the top of the carb off??? Common issue?

[blazingspider]

Might not be your problem but I had an issue once where the secondary throttle return spring had broken where the end of the spring inserts into the carb body. As a result, the secondary throttle would stay open rather than return to its normally closed position when at idle.

[So Cal Mark]

are you using an electric fuel pump?

[rebar1111]

Check your fuel line check valves for proper operation and installation, especially on the return-to-tank line.

[131]

Check your float isn't holed, take it out and shake it, if it has fuel in it it has a hole in it.

[Rupesy]

It's a diapragm pump on the side of the engine. I checked the brass float and it is empty. The only thing I keep noticing is that the distance keeps shortening and so I adjust it out again. However, I am not sure if it is the adjustment that is actually correcting the problem or if I am wiggling something els loose when I open it up. The only other thing I thought it might be is that the rubber pin is not seating properly. I know there has been some discussion on how ethanol is hard on seals.

Are there different style floats avaiable? I have a brass one that looks soldered.

[131]

The only other thing I thought it might be is that the rubber pin is not seating properly. I know there has been some discussion on how ethanol is hard on seals.

Are there different style floats available? I have a brass one that looks soldered.

There are plastic floats for different carbs, but brass is my preference. I'd be looking for a brass needle and seat, not the needle with the rubber tip. You shouldn't have to continuously adjust flat level.

[vandor]

What is your fuel pressure? It should be 2-4 psi. I've seen a defective mechanical pump that put out 15 psi! Fuel was dumping out of the carb! (side draft)

[majicwrench]

Is easy to have float rubbing on float bowl and thus not closing properly. Next time out, look carefully for rub marks on side of float and/or carb bowl.
Is also easy to have debris holding open needle, when you pull float it drops out, then everything works well.

Be careful and slow next time out, find the problem. SUper simple little carb.
Keith

[Rupesy]

Just a follow up....I bought a carb rebuild kit came with a brass needle and seat. Everything seems to be working great. I actually had to spend some time readjusting everything now that we got the fuel issue straightened out. Thanks for all the help. Hopefully I won't have to repost here!