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| Carburetor Identification (MerCruiser) Mercruiser Mercarbor Rochester? Mercruiser has used several different types of carburetors over the years. The Rochester 2 Barrel carburetor was popular on the early 4 cylinder models and it was also used on a few V6 and V8/305 GM engines as well. Rochester then stopped production so Mercury Marine designed its own version of the Rochester 2 Barrel Carburetor called the Mercarb. The Mercarb and Rochesters were mixed in production models. When ordering replacement carburetors, kits or parts you need to know exactly which carburetor your engine has. One simple test can distinguish between a Rochester and a Mercarb. The throttle base plate of a Rochester carburetor has two idle mixture screws. The throttle base plate of a Mercarb has only one idle mixture screw. If you have determined that your carb is a Mercarb, then there is one more identification you need to make. The Mercarb came with two different styles of accelerator pumps. One pump rod was straight and cut off flat at the very top. This was the older style. The other pump rod has a 90 deg bend at the top. This is the newer style.
Newer Style Accelerator Pump The earlier style Mercarb Kit (With straight accelerator pump rod) is p/n 3302-804845. The later style Mercarb Kit (With the 90deg bent accelerator rod) is p/n 3302-804844. The Mercarb Kits include all gaskets and seals, needle/seat, idle mixture screw, inlet strainer, springs, check balls, mounting gasket and accelerator pump assembly. Service Bulletin with helpful Mercarb Infomation and Tips. |
Older Style Accelerator Pump