The Trim Pump Coupler from Buckshot Racing #77 is a direct replacement for Mercury and MerCruiser OEM part numbers 89493 and 803852. This critical part connects the electric motor to the hydraulic gear pump in trim pumps, tilt pumps, and lift pumps.
When the coupler fails, hydraulic flow stops, leaving inboard or outboard drives inoperable. By meeting or exceeding OEM specifications, the #77 ensures reliable operation across Parker Oildyne units, Mercury Marine, Mercury Racing, Mariner, Bob’s Machine Shop, and MerCruiser (Merc Cruiser/Mercury Cruiser) systems.
Function and Design
In hydraulic trim and tilt systems, the coupler transfers torque while absorbing vibration between the motor and pump shafts. OEM designs such as Mercury 89493 and 803852 perform this job but wear over time from torque, heat, and vibration.
Our coupler maintains the same dimensions and tolerances, offering a precise fit that restores proper operation without modification, as a direct replacement part built to OEM standards.
Compatibility
The Trim Pump Coupler from Buckshot Racing #77 replaces Mercury OEM 89493 and 803852 across many MerCruiser, Merc Cruiser, and Mercury Cruiser assemblies.
It is compatible with Parker Oildyne 108/118 and 165/175 Series hydraulic power units, covering both AC and DC pumps, as well as Mercury Marine, Mercury Racing, Mariner, and Bob’s Machine Shop hydraulic pumps. This includes applications in trim pumps, tilt pumps, and lift pumps for both inboard and outboard systems.
Performance Parameters
The #77 coupler matches Parker Oildyne specifications. The 108/118 Series pumps operate at up to 207 bar (3000 PSI) with flows of 0.15–0.9 gallons per minute. The 165/175 Series reach 241 bar (3500 PSI) with flows of 0.75–1.4 gallons per minute. The coupler functions reliably within these ranges, ensuring torque transfer under real-world conditions in inboard and outboard systems.
Installation
Installation mirrors OEM service. Disconnect the battery, remove the pump assembly, and separate the motor from the pump. Replace the broken coupler with the new Trim Pump Coupler; align the shafts, and install with the correct orientation (it only fits one way up). Use 2-4-C Grease to insulate from water and over vibration, then reassemble. Once reinstalled, cycle the system to confirm smooth trim and tilt operation. During service, inspect seals, fluid, and shafts for wear to prevent future downtime.
Use in Performance and Racing
Reliability is especially critical in competition. A failed coupler disables trim, tilt, or lift pumps, often ending a race. The Trim Pump Coupler from Buckshot Racing #77, replacing Mercury OEM 89493 and 803852, is proven in offshore, inboard, drag boat outboard, UIM, F1H2O, APBA, USF1, and outboard circle boat racing.
Teams can keep spares in trailers and shops to avoid missed heats, as the coupler can be swapped quickly with basic tools.
Optional Dealer Pack: Buy 10, Save $30 at Checkout.
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com.