While snagging parts for a member with a bent throttle shaft I came up with this simple tool/fixture, it really helped remove the screws with no drama even with "pre fuggled" phillips slots. Sorry grabbed the wrong camera got blurry pics, stick is about 3/4 x 1". Clamp it in a vice, butt resting on the vice screw for support. Just shaped a stick with hand tools, 15 20 minutes total, this will aid in assembly as well as removal. Note the groove to capture the shaft, slotted to clear the brass tube, and bit of a bevel on one side to clear the butterfly. This lets you really bear down on the screwdriver to save the slot without the need for three hands to hang on to everything or the pressure bending the shaft.
Use some lube on the back of the screws before removal. They are staked, the lube helps keep from tearing up threads on the soft brass throttle shafts. Even better is to file away the staked part of the screws BUT this is fussy fine work, very easy to nick up the carb bore butterfly shaft etc. Don't attempt filing if you are not a bit OCD and willing to TAKE PLENTY OF TIME and care.
When the screws and butterfly are out you need to carefully deburr the throttle shaft front and back, at the screw holes, there will be a bit of swarf sticking up that will scratch up the throttle body bushings on the way out of the carb.
The throttle shaft is chrome plated brass, IE it's soft and easily damaged. Don't aggressively polish the butterfly, being brass it can quickly wear away, corners can round destroying the critical sharp edge needed to get the idle right.
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BS34 BS38 bs34s bs38s butterfly throttle shaft tool oak wood vice clamp impact hand JIS phillips butterflies seal seals guide removal remove burr strip stripped drill stake staked gggGary OCD nuts LOL bit allen hex replace replaced pine flooring stick rod dowel. leak air idle vary runon hang plate bear leverage crack clink
Use some lube on the back of the screws before removal. They are staked, the lube helps keep from tearing up threads on the soft brass throttle shafts. Even better is to file away the staked part of the screws BUT this is fussy fine work, very easy to nick up the carb bore butterfly shaft etc. Don't attempt filing if you are not a bit OCD and willing to TAKE PLENTY OF TIME and care.
When the screws and butterfly are out you need to carefully deburr the throttle shaft front and back, at the screw holes, there will be a bit of swarf sticking up that will scratch up the throttle body bushings on the way out of the carb.
The throttle shaft is chrome plated brass, IE it's soft and easily damaged. Don't aggressively polish the butterfly, being brass it can quickly wear away, corners can round destroying the critical sharp edge needed to get the idle right.
search terms
BS34 BS38 bs34s bs38s butterfly throttle shaft tool oak wood vice clamp impact hand JIS phillips butterflies seal seals guide removal remove burr strip stripped drill stake staked gggGary OCD nuts LOL bit allen hex replace replaced pine flooring stick rod dowel. leak air idle vary runon hang plate bear leverage crack clink
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