Yanmar Not Pumping Water? Expert Raw Water System Diagnostics in Kemah & League City, TX
A functioning raw water cooling system is the lifeblood of your Yanmar 2GM20F diesel engine. When your engine isn’t drawing water, it’s a critical issue that can quickly lead to a serious overheating event. It’s smart to start with the most likely culprit—the impeller—but as you’ve found, the problem often lies elsewhere. It can be a difficult-to-reach clogged hose or another issue in the system.
At Yes Centers, we specialize in comprehensive marine engine diagnostics, including the troubleshooting of raw water systems on engines like the Yanmar 2GM20F. Our certified technicians have the experience and tools to get to the root of the problem, saving you time and frustration. We bring our expertise directly to your vessel in League City and Kemah, providing reliable, dockside service.
Troubleshooting Your Yanmar’s Raw Water System
You were right to change the impeller first—that’s the most common cause of cooling failure. However, when a new impeller doesn’t solve the problem, our technicians will systematically investigate the entire raw water path, looking for these common culprits:
Blocked Seacock or Strainer: The most frequent issue is a blockage at the very start of the system. Barnacles, marine growth, or debris can clog the seacock inlet on the hull. We’ll check and clear this intake, as well as the raw water strainer basket, which often catches debris.
Collapsing or Clogged Hoses: The hose from your seacock to the raw water pump is under negative pressure, which can cause an old or non-reinforced hose to collapse and prevent water intake. We will inspect this and other hoses for blockages, kinks, or signs of dry rot that could be letting air in.
Air Leaks in the Suction Side: A raw water pump needs an airtight seal to create the vacuum required to pull water from outside the hull. An air leak can be caused by a cracked strainer lid, a loose hose clamp, or a worn-out gasket on the pump cover plate. Even a tiny leak will prevent the pump from priming.
Worn Pump Housing: Even with a brand-new impeller, a worn-down cam or a scored faceplate on the pump housing will prevent the impeller from making a tight enough seal to draw water. We’ll inspect the pump body to ensure it is in good condition.
Downstream Blockages: The problem might not be on the intake side. A blockage in the heat exchanger’s small passages or a severely restricted exhaust mixing elbow can also prevent water from flowing through the engine and out the exhaust.
Don’t Risk Overheating: Trust the Professionals
A failure to cool your engine can quickly lead to a major repair bill. While a blocked hose can be a simple fix, it’s often difficult to access in a cramped engine compartment. Our marine technicians are equipped with the right tools and knowledge to quickly and safely diagnose the issue, whether it’s a hidden blockage or a more complex problem with the pump housing.
Don’t risk a potential engine-ending overheat. Let the experts at Yes Centers get your Yanmar 2GM20F cooling system running flawlessly. We provide reliable service right where your boat is located in League City and Kemah, giving you peace of mind before you leave the dock.
Is your Yanmar 2GM20F not drawing water?
Request professional service by filling out our convenient online form or giving us a call:
Yes Centers 828 Marina Bay Dr, Kemah, TX 77565 +1 281-538-9377 https://yescenters.com/service-request-form/
