I have a question for all the Mercruiser Rochester Quadrajet 4 barrel gurus...

[rhillman75]

So my biggest issue is the spring that goes into the power piston. I got a master rebuild kit that came with the float and the guy (very reputable) gave me a spring for the power piston. When I went to tear the carb down and remove the secondaries. The existing spring was a different height compared to the one that the guy gave me. The original spring is more contracted and the new one is more spread out. I looked at several images on google and it appears there are more than 1 spring used. Should I use the original or go with the taller one. The one that he gave me does not lock into the piston as the original one does. I also had a question about the "epoxy" trick concerning the leaking of the secondaries. The carb is pretty dirty, but I don't know if I should start modifying it with a new spring or an epoxy job. The carb number is 1708-0561 and the metal tag says 1347-9662. Is there a really good manual that pertains to just this carb out there?

 

[NHGuy]

That spring is what raises the power piston when vacuum drops off. It's one of the parts used by tuners to set up carburetors. By selecting different springs your carb man determines the rate and height that the metering rods move to allow fuel into the circuit.
If you trust your guy, use the spring he sent. If you aren't sure, ask him.
Then if it's too long you might need to stake the top edge of the bore to keep it in place.