Mercury Marine Mercarb Carburetors

 

What is a Mercarb carburetor?

 

 

 The Mercarb is a redesigned and improved version of the Rochester Twojet carburetor.  Mercury Marine used the Rochester Twojet carburetor for many years on 4, 6 & 8 cylinder engines.  Mercury Marine redesigned the  Rochester Twojet carburetor and started making the  Mercury Marine Mercarb carburetor.  The Mercarb is very similar to the Rochester Twojet carburetor, but some parts are different.

 

 How to tell whether you have a Mercarb or Twojet carburetor

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•  The Rochester Twojet carburetor has two idle mixture screws.
• The Mercarb only has one idle mixture screw.

There are two rebuild kits available for the Mercarb

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If you dont know the carburetor number, the best way to determine the correct Mercarb rebuild kit is to look at the accelerator pump stem.

• Early style Mercarbs used an accelerator pump with a straight stem.
• Later style Mercarbs used an accelerator pump with a 90 degree bent stem.