Italian IDA's, pump jets leaking

[Stefan Rossi]

i have a pair of italian 48 IDA's i brought off here a year ago.
they have had the Jaycee fuel inlet, 3rd progression hole added and the float bowls enlarged

but one of the carbs has a problem

the left hand one is permanently leaking fuel out of both pump jets, even when not revving.
have stripped the carb down many a time and even removed the cam and push rods that opperate the pump jets, i was told maybe the two push rods in the left carb were too long, but messuring them to the right hand carb they are not.
have also swopped the push rods from right to left and this hasnt made a difference and the left one still leaks

the float isnt perferated so no problem there

i am using a cb 3.5 psi pump with a holley regulator (which doesnt seem to do anythink) and on using 2 pressure gauges reads hardly any psi :s

we took both fuel lines off and they both filled each cup equally when the ignition was turned on. so there is fuel pressure there constantly

its gotta be some problem with this lef hand carb

im just scared now after all these test this carb may be fucked and i cant really afford to replace it at the moment

has anyone any ideas at all? kind of new to IDA's and we are all baffled now! hence this thread!

cheerz

stef

[Martin]

you have to adjust the pump cam, what happens is that when the motor is idling the vibrations tickle the pump and cause a dribble from the accelerator pump jet.

Martin

[Stefan Rossi]

thanks very much for that info! ill get onto it asap and let you know if it stops the problem!

fingers crossed it will!

stef

[Bruce]

you have to adjust the pump cam,

The problem is, the pump cam isn't adjustable.

Advance your timing.  This allows the throttle plates to be more closed at idle, retracting the pump cam from the lever.

[Martin]

you can buy an adjustable cam / or make one.


Martin

[Eric Ellis (57HotrodVW)]

you can buy an adjustable cam / or make one.

Martin

Yep. GB 532-W

http://www.geneberg.com/cat.php?cPath=8_282_2868

[Jason Foster]

could be the shaft is tweaked.  letting one barrel close early while holding the shaft against the cam causing the dribble.  take carb off drain it and then hold it up to light looking down the throats. You are looking for light leaking around edges of one butterfly. They of course should be equally sealed.  Hope that makes sense.