carbuetor flooding

I have done a total rebuild on my 79 MGB engine. New cam, lifters, rockers, timing gears and chain, .020 over pistons, Stromberg 175CD from propermg.com, crank turned, etc. My problem is the carburetor is flooding, I have adjusted and readjusted and it still floods. I dry out the plugs and restart the engine and it runs a few minutes and dies from to much gas. Coil is putting out a great spark, any ideas?

fuel pump putting out too much pressure
float bad, filling w/gas
needle valve stuck

Thanks for responding iggy. But last night I rebuilt the new carb. and readjusted the good float and installed another needle valve, the pump seems to be ok�.it must be in the choke but I don�t know how to check.

Larry - Do not start that engine again without getting your flooding situation under control. Repeat - don't start that NEW engine again. You'll wear out the rings in no time.

Take the piston out of the carb and turn the ign. switch to run position. Look at the jet. If gas is running out of it you have one of the above problems. The choke sticking wouldn't flood the engine as quickly as you described. It would foul the plugs after the eng warmed up. I suspect you may have too much fuel pressure it everything elase is correct as you say. You are sure you got the floot in correct I guess. It will go in upside down.

I did set float to spec., although I really don�t trust the spec. It says 5/8 at the highest point. At that level it is not parallel with the base. As David has indicated about the rings, I am going to ruin the rings if something does not change soon. Maybe I should forget the spec and lower the gas level in the chamber?

Where did you get the 5/8 figure. I have always set the parallel with the face. I assume you did put the washer under the needle. Also if you dumped gas in you oil you will stand a chance of rod bearing failure.

On fuel pressure, I used to buy a small inline pressure regulator, name on the back is "ProFuel" at what is now O'Reilley's. It's adjustable, one half to five and a half in half-pound steps. Price was such that I had one on the race car, one on the street car, and two spares in the track box. Still have one on the Pinto.
On diluted oil, 'twere me, I'd drain & refill as soon as the carb problem is solved. Oil's cheaper than engines.
On the carb, listen to Tom. Or David. Anybody but me.

Ask somebody else about those ZS carbs. I haven't worked on one. Don't intend to start anytime soon. Best of luck to you.


PS - I've got a spare Weber DGV + manifold if you are interested.

The Haynes Manual says �floats must be adjusted parallel to and within 0.625 to .672 in of the face.� Tom, could I be misinterpreting the statement? I thank you all for this help. Changing the oil is a good idea.

Tea, were did you get the 5/8th

.625 = 5/8"

Maybe it should be thousandths.

I have only had one sip of coffee.

larry, either get a pair of su hif4's & manifold or a weber dcoe &manifold for performance or a dgv & manifold if you don't want performance over economy. end of problem.... happy trails

Are you sure you don't have the float installed upside down?

Chris, I been having the same 1 cup problem on this problem for several weeks now, but thanks

Tom, I doubled checked the float as to being right side up. I am so gun shy to experiment now because of the potential to ruin the rings and rods. Although when the engine has run fairly good for short periods, could I have something in the timing wrong? I have checked to see the valves are roughly in the right places when #1 is TDC on compression stroke. I am totally lost at this point, I must be missing something. I do have many many years of MG hobby experience.

Jerry, I almost did the Weber thing last week, but when you have so much $ in this engine already you have to wonder when to stop. I can�t stop till the engine is running great, but must try to make this Z work. In the end I may have to do as you recommend.

I didn't read all the posts, but the water choke is crap. Pull off the water jacket/thermal spring housing, block the choke lever fully CCW and see if it makes any difference. Float level at 5/8 inch didn't work for me. Too lean. You may have to mess with it a little. My guess, though is a leaking float valve. Do you have the one with the ball bearing type insert. I tossed the one that came with the kit. Leaked!!!!

Jacket is off, been trying to figure if it should go CW or CCW..Thanks for the info. I will try that

You all know what I think of ZS carbs in general, and ZS carbs on MGs in particular. They can be forced to work, but donkey's can be forced to dance. -- that doesn't mean they want to. If you really want the engine to run well, and not be hamstrung by a bad carb/manifold design, go with one of the alternatives. Which one is up to you, and each has advantages and disadvantages to sort out, but IMHO, ALL of them are better than the ZS and that awful manifold.

Unbelievable.. the engine is running, and fairly well right now. Baxter you are probably right, but as I said before, got to much money in this stuff at the moment. The final problem I think was the float level needed a little attention, but most of all I had adjusted so much that I had the needle adjusted so lean it had cut off the fuel, but the choke was locked on all the way. Anyway disabling the choke and readjusting the needle seems to have fixed the problem. I just need to fine tune the adjustments now. I really do thank everyone. Does this make since? I may I done something else to fix that I am not aware of.

Glad it works better. Most CA smog places won't pass your car if the emissions has been changed, which includes the carb/manifold setup. Stupid, huh! Anyway, when you put the water jacket back on, be sure the tab is in the hole on the end of the thermal spring and that everything moves freely. To test the spring, take the jacket, put it in boiling water and mark where the loop end of the spring goes. It should be pretty close to the index mark. Set the new mark at the line on the carb body when you re-install it.