throttle shaft issues

[biggjimm]

I decided to go ahead & go thru the carb before heading to the lake as I couldn't get it to idle & it's been setting for about 3 seasons now. It's my '76 140 3.0L. Long story short, the heads of the little brass screws that hold the throttle plates in the shaft are broken off & the throttle plates just kind of move around in the shaft as you open the throttle. Any idea where a guy could source those from, outside of a donor base plate off another GM carb? It's a 2 barrel Rochester carb. with a mercruiser tag # 1351-5203A1 & the carb stamp is #7043184. If that matters. Thanks guys. Jim.

 

[biggjimm]

They are 6-32 so I suppose if I can find brass or SS screws with the correct head, I could just cut 'em to length & either stake them like they were from the factory or loctite them in place??
I guess I thought they were some kind of "special" or "magical" screw but I think I can probably pick something up at the local hardware. Jim.

 

[Grub54891]

Makes me wonder how they came loose, did someone have it out in the past? And is it messed up in another way. The plate has to be indexed exactly in the right plate, With the idle screw backed all the way out and plate set fully closed and seated, you snug up the screws and stake them. A little red locktite won't bother it at all, it's good insurance.

 

[Scott Danforth]

Ace hardware for replacement brass screws. Blue loctite would be sufficient.

More importantly is where did the heads go? I had a 4 barrel on a built Buick 4.1 I picked up that lost 4 of the throttle screws. Found them embedded in the tops of 2 pistons

 

[biggjimm]

Ace hardware for replacement brass screws. Blue loctite would be sufficient.



More importantly is where did the heads go? I had a 4 barrel on a built Buick 4.1 I picked up that lost 4 of the throttle screws. Found them embedded in the tops of 2 pistons

I'm guessing (hoping) that they went out thru the exhaust as small as they are. I've looked in cylinders w/ borescope don't see any sign of them.