Slow idle issue

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Chris G
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Slow idle issue

Looking for help on an idle issue please.

I have a Dellorto FHC2013A which will not idle or start unless I screw the idle in a fair bit  which will make the engines idle way too high.

This carb issue follows different engines, air filters, throttle bodies, all of which work fine with other carbs of the same type.

I have stripped and cleaned this carb. Is there an area I should focus on this carb for this low rev stalling issue?

Many thanks

 

 

Chris G
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Issue appears to have been

Issue appears to have been that the idle jet screw had been wound all the way in ....should have checked that before asking, working ok now..

wristpin
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The symptoms suggest an

EDIT . Just seen that you have solved the "problem" while I was entering the cleaning procedure. Leaving it in place as it may be useful to someone in the future.

The symptoms suggest an obstruction to the idle / slow running circuit. At the best it may be cleared with an aerosol of carb cleaner and at the worst will require the removal of the welch plug covering the gallery over the idle passages. The idle mixture is introduced to the venturi by two very small drillings just visible where the throttle butterfly touches the venturi wall when closed .

Remove the idle mixture screw above the word Dellorto and introduce an extension tube from the carb cleaner as far into the carb as possible; the tighter the fit the better so that the full force is directed inwards. In addition, at the choke end of the carb, to the right of the butterfly shaft there is a small brass jet which will should be blocked to contain the pressure within the idle circuit. Easily done with a cotton  bud pressed over it. 

Now squirt the cleaner while observing the two small drillings in the venturi. Hopefully this will result in two small jets of cleaner  - usually one larger than the other. If there is a restriction in either of those drilling it may be possible to clear it with a piece of fine wire bent at right angles about 2mm from one end. Hopefully, if fuel can now pass through the idle circuit , this will result in a satisfactory idle mixture but if it doesn't the next step is probably ultra sonic cleaning. If that fails, it suggests a blockage behind the welch plug that lies above and to the left of the idle mixture adjustment screw. Careful removal of this plug should enable it to be reused but suitable plugs are to be found in "chainsaw repair assortments".      

Chris G
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Thanks for this Wrist Pin.

Thanks for this Wrist Pin.

Short of removing the welch plug I am going to follow this. I had given this carb a thorough ultrasonic clean but its not a panacea to all dirt removal, especially if dirt is "trapped" and cannot be broken down.