Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 107Get this manual
5 Install emulsion tube
Carburetor Jet Installation
1Install idle air jet and back draft vent jet2Install off-idle air jets
51862Emulsion Tube
bGasket
aOff Idle AI( JetIdle Air JetVent Jet
PlugInstall gasket and fuel bowlSecure in place with five retained screws
Install main (high speed) fuel jet and access plugs with gaskets