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Dellorto side draft throttle sticking


burrowssj

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Hey are there any Dellorto experts out there? My throttle is sticking and I've tracked it down to the rod which runs through the two ports and the butterflies attach to the rods(throttle shaft is tech term). Tried to free it up with crc but no luck. Any ideas? It was sticking completely but now after me playing with it just doesn't return fully (e.g idles at 2000 RPM). You can return it by hand find so something is definitely sticking internally. Carb was fully rebuilt about 8months ago. Car is a  1600 xflow cortina with a single side draft 

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they are pretty simple mechanically, you should be a ble to spot it, but you might need to pull it off the manifold

 

could be

- something jammed in there,

- one of the springs or tabs on one end of the throttle shaft has shifted or come loose/catching on something?

- butterfly come loose?

- throttle shaft a bit bent (they run on bearings)?

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they are pretty simple mechanically, you should be a ble to spot it, but you might need to pull it off the manifold

 

 

- one of the springs or tabs on one end of the throttle shaft has shifted or come loose/catching on something?

 

+1 for that mine was doing turned out I was missing a spring

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Should note I had the carb fully rebuilt by palmside 6-8months ago. Yea I'm thinking my next move is to put another larger return spring on it. 

 

Seems strange that it would be working fine for that long then overnight it some how gets stuck and prevents the car being started(floods straight away)

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If it was workign sweet for 6-8 months then its not palsides fault. If it is a sudden change then its something that has suddenly changed to cause this.

 

what i mean is you should find and fix the issue properly, instead of masking it with more force.

 

should return to closed without a large® return spring (on the accellerator cable or whatever) there is a small coil spring on the end of the throttle shaft(s) which is more than capable of snapping the throttle closed - if this isnt working propertly theres something wrong (could be that very spring of course).

 

Its probalby something dumb like a nut comeing a bit loose and letting something catch.

You also said its flooding? non-closed butterflys will let in more air & fuel so will be running on idle/transition or main circuit rather than just too much gas? ie will 'idle' really fast.

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make sure the butterfly screws havnt come loose as they can shift around in the shafts causing them to jam if so loosen them off but dont remove the screws and snap open and close the throttle a few times with the idle screws backed off the butterflys should re seat then re tighten the screws

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  • 2 weeks later...

Stupid comment but gonna say anyway, is your return spring at a 90 deg to your spindle shaft?? If it's on an angle it will pull on the bearings in the carb body instead of the spindle therefore uneven load on butterfly's

Are they twins??

What kind of cable and shaft setup are u running?

Sorry bout the questions carbs are a bit of a passion for me

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