FOUND.....throttle pusher or throttle dashpot.....

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6cuda6

Active member
Oct 3, 2019
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Ontario, Canada
GMC calls it a throttle pusher....lots of people call it a dashpot....no matter how you call i need a working one.....found one20200518_171714.jpg
 
Last edited:

JSanford

Member
Oct 4, 2019
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Sacramento, CA
The pn in the parts book is 550623. I searched all over and that throttle pusher was only used on the GMC motorhome.

Mine was disconnected and the hose plugged because the plastic part of the pusher had cracked. I searched and couldn't find a replacement so I actually tried gluing the plastic and surprise surprise it actually works!

I have a California 1977 455 and this is my pusher. Not sure why it looks so different.
IMG_6609.jpg
 

tmsnyder

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Oct 7, 2019
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Buffalo NY
Isn't this just an emission add-on? I thought it was meant to slow part of the carb down to reduce emissions, either slamming shut or opening too quick, can't remember exactly. Check it out, maybe it's not actually needed.
 

6cuda6

Active member
Oct 3, 2019
299
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Ontario, Canada
Isn't this just an emission add-on? I thought it was meant to slow part of the carb down to reduce emissions, either slamming shut or opening too quick, can't remember exactly. Check it out, maybe it's not actually needed.
Correct, its part of the emission system and its job really was to hold the throttle open slightly, in gear, when closing to prevent over fueling because the throttle blades are slammed closed creating a flooded condition.....it also creates a really bad stumble when its not working on initial throttle application when set up for it.

Some manufacturers also use it as an idle boost for vehicles with engine power A/C systems to boost the idle when the compressor comes on to avoid the compressor engagement drawing down the engine RPM to low.

Can it be eliminated, yes but then the carb has to be completely reset for the it not being their [not a bit deal really] but i would just rather it be there..
 

tmsnyder

Active member
Oct 7, 2019
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Buffalo NY
Ok, at least it's good to know for a backup plan, just in case that thing turns out to be made of unobtainium.



Correct, its part of the emission system and its job really was to hold the throttle open slightly, in gear, when closing to prevent over fueling because the throttle blades are slammed closed creating a flooded condition.....it also creates a really bad stumble when its not working on initial throttle application when set up for it.

Some manufacturers also use it as an idle boost for vehicles with engine power A/C systems to boost the idle when the compressor comes on to avoid the compressor engagement drawing down the engine RPM to low.

Can it be eliminated, yes but then the carb has to be completely reset for the it not being their [not a bit deal really] but i would just rather it be there..
 

6cuda6

Active member
Oct 3, 2019
299
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Ontario, Canada
I think i got one coming off Flee-Bay....slightly different lever end but the vacuum can and mounting are the same.....here's hoping i'm not going down the complete system replacement road.....