OMC Cobra Raw Water Intake Vacuum Test Kit

Product Description

Operational Instructions

This adapter kit is designed to test the integrity of your raw water intake system by allowing you to pressure/vacuum test the water passages in segments.

Requirement: This kit requires a Mityvac hand pump (or equivalent vacuum/pressure tester), which is widely available at most automotive supply stores.

Segment 1: The Sterndrive Internal Housing

This step tests the lower gearcase up to the water pump area.

1. Seal the Inlet: Block off the lower water intake grates on the sterndrive using the supplied large adhesive neoprene pads on both sides of the gearcase.

2. Mount the Tool: Place the supplied soft rubber gasket onto the sterndrive's impeller housing location, align your custom adapter plate over it, and bolt it down securely.

3. Run the Test: Connect your Mityvac to the right adapter nipple and pull a vacuum.

4. Diagnosis: If the system cannot sustain a vacuum, you have broken seals in the sterndrive’s internal water collector, which consists of several gaskets, grommets, and the copper connector pipe.

Segment 2: Transom Assembly to Engine Feed Hose

This step tests the path from the sterndrive, through the gimbal housing, and up to the engine.

1. Isolate the Line: Disconnect the raw water feed hose where it plugs into your engine's thermostat housing/distribution block.

2. Plug the Hose: Insert the supplied hose plug into the disconnected hose and secure it tightly with a hose clamp.

3. Connect the Tool: Ensure the adapter plate is still securely bolted down with its rubber gasket, then connect your Mityvac to the left adapter nipple.

4. Run the Test: Apply vacuum (or low pressure) and observe the gauge.

5. Diagnosis: If it leaks, you need to examine the plastic hose adapter (water pocket cover) and the rubber molded hose inside your external gimbal assembly. Examine your oil cooler canister between hoses for rot or delamination of one of the copper covers. This is where they usually split.

6. Pro-Tip (Leak Detection): If you are having trouble finding the leak, you can introduce water into the system through the adapter plate using the Mityvac. Water will visibly weep out exactly where the line is compromised.

Final Critical Recommendation

If both segments successfully hold a vacuum, your leak is likely at the final connection point.

WARNING: Replace the short rubber hose that connects directly to the installed impeller cover. Do not improvise or use a generic automotive hose here. You must buy an OEM replacement. The wall thickness, diameter, and the subsequent attachment grommet are tightly calculated for proper operation and sealing under suction.