My current stommies are "tired" so I opted for a set of Alan's looks good value at the price 
Carbs fitted yesterday, initially absolutely superb, balanced them perfectly, even before tuning the engine runs so much better than my old carbs which I cannot get below 8% CO.
Then when checking CO (which needs the engine to run at idle for 8 minutes plus) the car faltered slightly after 7 mins of idle, a quick rev saw it ok, but the CO readings were all over the place. Got it so that after running at 2k rpm for about a minute and then letting it settle back to idle the CO reading was just over 4% for 30 seconds or so but then crept back up to 12% over the next 2 mins.
Switched ignition off and removed both dash pots and pistons to check the needle lengths and to make sure nothing was amiss and on RH O/S carb, fuel squirted out of the jet hole for a second or two and then settled to a trickle for the next 5 mins. I removed the set and checked float height (17mm) and that the needle valve was working (I could suck on the fuel inlet and slick my tongue over it to hold a vacuum for 5 sec plus) Re assembled and fitted to the car.
New pedestal o-ring had already swollen!!! ended up cutting and shutting the damn thing while setting up.
After reinstalling I tried to start after cranking for 30 seconds or so and the rh carb (o/s) flooded badly, fuel flooding out of the vent pipe that goes via T back to the airbox, did it so bad that the airfilter box and both elbows had traces of raw fuel in them! I removed the breather pipes and with ignition on the fuel would come out at the RH vent tube on the elbow 2 seconds every 7 if you get my drift. So it would pump fuel for 2 seconds then be clear for 5 seconds then pump fuel for 2 etc
No fuel came out of the overflow!
The float floats, is flat side down, and 17mm from gasket face to bottom of float near the pivot, the needle valve closes and passes the vacuum test. It was then that I noticed....
The bracket that holds the pin that the float hinges off, is fixed to the carb body in two places by the ally being pined over. On the RH carb it is not fixed on the pin that is closest to the needle valve. In theory this shouldn’t impact as I suspect the float and everything is pushing upwards but if the needle valve needs more effort to close than the mounting needs to move it could cause the float chamber to flood. Does that make sense?
Before you suggest fuel pressure or contamination. Filter is clean and was fitted last year 400miles ago . The tank is spotless and I have had this current fuel pump for 4 years. Anyway the old set of carbs were refitted immediately after the major flooding incident and although running rich did not flood. With the system at pressure i.e. ignition on I lifted each dashpot piston and the barest whisper of fuel came out of the jet.
Do you think maybe needle valve of should I attempt to fix the mounting to the carb body better?
Richard
Carbs fitted yesterday, initially absolutely superb, balanced them perfectly, even before tuning the engine runs so much better than my old carbs which I cannot get below 8% CO.
Then when checking CO (which needs the engine to run at idle for 8 minutes plus) the car faltered slightly after 7 mins of idle, a quick rev saw it ok, but the CO readings were all over the place. Got it so that after running at 2k rpm for about a minute and then letting it settle back to idle the CO reading was just over 4% for 30 seconds or so but then crept back up to 12% over the next 2 mins.
Switched ignition off and removed both dash pots and pistons to check the needle lengths and to make sure nothing was amiss and on RH O/S carb, fuel squirted out of the jet hole for a second or two and then settled to a trickle for the next 5 mins. I removed the set and checked float height (17mm) and that the needle valve was working (I could suck on the fuel inlet and slick my tongue over it to hold a vacuum for 5 sec plus) Re assembled and fitted to the car.
New pedestal o-ring had already swollen!!! ended up cutting and shutting the damn thing while setting up.
After reinstalling I tried to start after cranking for 30 seconds or so and the rh carb (o/s) flooded badly, fuel flooding out of the vent pipe that goes via T back to the airbox, did it so bad that the airfilter box and both elbows had traces of raw fuel in them! I removed the breather pipes and with ignition on the fuel would come out at the RH vent tube on the elbow 2 seconds every 7 if you get my drift. So it would pump fuel for 2 seconds then be clear for 5 seconds then pump fuel for 2 etc
No fuel came out of the overflow!
The float floats, is flat side down, and 17mm from gasket face to bottom of float near the pivot, the needle valve closes and passes the vacuum test. It was then that I noticed....
The bracket that holds the pin that the float hinges off, is fixed to the carb body in two places by the ally being pined over. On the RH carb it is not fixed on the pin that is closest to the needle valve. In theory this shouldn’t impact as I suspect the float and everything is pushing upwards but if the needle valve needs more effort to close than the mounting needs to move it could cause the float chamber to flood. Does that make sense?
Before you suggest fuel pressure or contamination. Filter is clean and was fitted last year 400miles ago . The tank is spotless and I have had this current fuel pump for 4 years. Anyway the old set of carbs were refitted immediately after the major flooding incident and although running rich did not flood. With the system at pressure i.e. ignition on I lifted each dashpot piston and the barest whisper of fuel came out of the jet.
Do you think maybe needle valve of should I attempt to fix the mounting to the carb body better?
Richard
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