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high & low needle valve settings

dannisdan's Avatar

Join Date: Jul 2013
Posts: 1

07-13-13, 12:48 PM   #1  
high & low needle valve settings

i have a 32cc craftsman weed wacker model # 358 791071, it looks brand new. i cant get it to idle or r up (it will run just above idle if i hold throttle wide open) i have turned both needles and could get any more than a high idle at full throttle. i have since learned i had the plug gapped wrong...long story short what should i set the high & low screws at to start over. and which screw is high and which is low? thanks for any help and or advice.

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marbobj's Avatar

Join Date: May 2006
Posts: 3,658

07-13-13, 05:03 PM   #2  
Those are usually marked "L" & "H". There is also a screw to set the idle speed as a throttle stop.

Turn both L/H screws in until lightly seated - don't force them any. Then turn both out 1 1/2 turns. Now set the idle speed until you can keep the engine running.

Turn the L screw in or out until you get the max rpms. then slightly out to get a small drop in rpms. Then go to the H screw with the throttle wide open, set it for max rpms, then slightly out for an rpm drop.

Now check engine for throttle response. It should snap right open. If it"s sluggish, adjust the H screw in until you get a snappy response, then repeat the adjustment for the H screw with the throttle wide open.

Be sure to always do the last step to drop the rpms. This gives the engine a cooler air/gas mixture and prevents engine damage.

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