Mercury Marine 700 SCi Harmonic Balancer External Balance

Dual Keyway Option

The double keyway option requires that the factory or aftermarket crankshaft be removed from the engine and a second keyway cut into the snout of the crankshaft. DO NOT run a double keyed damper on a crankshaft without the double keys. Failure to the damper hub can happen without the supporting key in the broached keyway slot. The dual keyway option is for Supercharged or Extreme Duty Applications (typically over 750 rwhp). Without the double key modification your crankshaft in these high horsepower applications can lead to the failure of the damper hub and/or the single keyway which results in damage to the damper and the crankshaft snout. '
Externally Balanced Harmonic Balancer for High Performance 700 SCi Mercury Marine Sterndrive Engines with SFI 18.1 Rating for the highest quality. The Balancer features an all anodized aluminum case design for light weight, stress-proof steel hub and 1040 steel inertia rings for durability. Wet clutch friction design style with precision machined harmonic dampening for street and race engines.

• Anodized for corrosion protection in fresh water and salt water applications.


• For External Balance Applications Only.


• Exceeds SFI 18.1 standards and is marked on front with SFI Sticker, and on the rear with SFI number stamped into unit.