Newbie still puzzeled about flooding carb

[metonzed]

It's me again, the one with the question about the anti run-on valve, in which you guys thankfully set me straight.I had gulps and runs mixed up. Anyway we determined I may have a stuck float which was causing fuel to run out the canister. Well, the flooding out the canister is still giving me fits. I took both carbs off, removed the floats and needles, chem-tooled and blew everything out(wasn't dirty or gummy),wrestled the carbs back in and gas still runs out the canister. I can hear a little ticking going on after a shut it down, which I assume is the fuel pump. Am I going insane? What else could cause a torrent of gas to come out the canister? Supposedly the carbs had just been rebuilt.The thing is, it ran like a champ right before. I have probably put 250 miles on the little beast since purchasing it. Advice appreciated........

 

[bob67bgt]

If the carb vents are plugged the floats will not shut off the fuel supply correctly.Try removing the metal connector line that connects the carbs and then has the line that goes to the canisters. Run seperate fuel overflow lines from the carbs down toward the ground (like the earlier MGBs). You should see which carb is flooding or determine if there is a problem with the canister not venting the carbs correctly. I am assuming you are running a proper SU fuel pump. If you have one of those ticky box fuel pumps it may have too much pressure for the needle and seats to handle causing your problems. Good luck with the little beast! Bob

 

[DrEntropy]

Do what HE says. I live in Florida, there are some bugs here whut'll build "nests" in tubing. Mud daubers. THOSE critters have been known to block off more'n one vent tube too... It always ends up bein' something simple (silly). Look for th' "dumb stuff" first. Blocked vents or an overpowering fuel pump. The carbs don't like anything much over 3.5~4 PSI. Usin' Bob's guide you will isolate which carb or device (canister or pump) is at issue.

And let us know of your progress! We need to know if we've hit or missed, willing to lend advice until it's solved. Ya took th' time to find this place, we'd hate to see ya leave... we now know where you live.

 

[metonzed]

Thanks .....I have taken both vents off previously to try to islolate the offending carb, which is the forward one BTW. I do have a ticky fuel pump but it doesn't seem to bother the rear carb. Again, it was running great and then for no apparent reason just started flooding. I love the way MG vents the overflow right on top of the starter BTW! Why don't they just direct it toward the exhaust manifold and get it over with!

 

[DrEntropy]

You haven't seen the earlier cars, then...

Must be a needle/seat/float issue in the chamber if it's just the front one pushin' out the overflow. Are the float needles the Viton tipped ones? If it has the "Grosse Jet" needles, I'd be for changing them. Some think they're good but a lot of racers and experienced wrenches consider 'em junk. I'm with th' latter camp. Float intact?

For it to have SUDDENLY started this, there should be something fairly evident. Float full of fuel, needle valve not seating.

To test the needle the carb needs to be off the engine (again) and after removing the fuel and the bowl gently blow into the fuel inlet as you raise the float. It should "plug" and shut off your air flow as the float reaches the set level.

 

[David_DuBois]

If by "I do have a ticky fuel pump" you are referring to the little square, run all the time, make a lot of noise, facet pumps, you may have a pressure that is right on the ragged edge of being too high. There are numerous models of the Facet pumps, several that are a perfect fit for MGs and some that are marginally high and finally some that are way to high. The fact that it is only one carburetor that is being affected, leads me to believe your pump falls in one of the first two categories. The best approach at this point is what Bob and Doc have suggested - check the needle valves and float (switching floats between carburetors to insure that you don't have a flooded float would be in order). The Gross Jet valves of 25 years ago were wonderful valves that cured a lot of problems. Since that time, the company has been sold and the product put out now is crap. Since there is no way to tell if a gross jet that is installed is old or new stock, the best approach is to remove them and replace with the vion tipped needle valves.
Cheers,

 

[metonzed]

Thanks again for all the great help.....I thought I would let you guys know what the problem turned out to be. After all the messing around I discovered I had a tiny leak in the float itself. This would explain why it would run awhile then spew gas out the overflow. So thanks again, I'm sure I will be tuning in again when the little beast decides to act up !