Mercury Powerhead Interchange


Basically all V6 Mercury 2.0, 2.4, and 2.5 liter outboard powerheads are about the same. Meaning they all have the same bolt pattern at the bottom and will technically interchange or bolt on to any year mid section whether standard bass mid, Mercury Racing of Mercury ROS (race offshore).

In most cases, there are two points to consider. 1) the stud lengths vary from mid section to mid section so you may have to change the studs in the powerhead. 2) The exhaust exit shapes/sizes are mainly of two varieties... square or a larger rectangle shape. Most of the race or high performance motors have the rectangular shape accept for the 2.0 Liter SST-120. If you have a powerhead with the smaller exhaust exits, like a SST-120, 135 hp or 150 hp fishing outboard you can bolt them safely to either the square or rectangular shaped mid-section.

You can also consider changing the exhaust tuner, which is the top plate of the mid-section that meet-up to the powerhead, to match your exhaust exits on the powerhead. The older style tuners are two piece and sandwich the top motor mounts while the newer style race tuners are generally one piece with the motor mounts as part of the structure. The tuners, both one piece and two piece, are also universally interchangeable between mids and powerheads.

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Mercury 2.0 Liter

Exhaust Base Plate Gasket: Part # 27-99776 1 This gasket goes between the powerhead and the mid section. You will need two if you have race cowling or just one if you are running the calm shell cowl.

Two-part Tuner Plate Gasket: Part # 27-99177 2 This gasket goes between the two halves of the 2-piece tuner.

Drive Shaft Exhaust Base Plate Gasket: Part #27-99173 4 This gasket goes under (or below) the tuner and above the exhaust can. (mid