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STORIES IN THE MAKING

Smarter Materials, Fewer Failures: Meet MC97

Robin Blank Johnson Pump Marine Recreational Marine Products

Built to Perform: Why Johnson Pump Marine Impellers with MC97 Deliver More Than Just Flow

In marine systems, reliability isn’t optional; it’s essential. Whether you’re designing propulsion systems for boats, engineering engine cooling for inboard power, or relying on your boat’s pump to keep your engine running cool on the water, every component has to work, every time. That’s why Johnson Pump Marine goes beyond just building pumps. We engineer confidence into every impeller, starting with the material.

Unlike many marine pump suppliers, Johnson Pump Marine doesn’t rely on generic rubber compounds or materials. We formulate our own: MC97, a proprietary compound designed to outperform standard neoprene in both durability and consistency in leisure engines, especially in marine environments where downtime and saltwater are a given.

Neoprene has long been a go-to material for flexible impellers, but it's not without its flaws. When a neoprene impeller isn’t used for extended periods, common in leisure boats and generators, it will swell as it absorbs water. That swelling leads to blade deformation, higher friction, and sometimes even hub separation. In worst-case scenarios, it can cause pump failure right when the system is needed most.

MC97 resists water absorption, meaning it doesn’t swell over time. That makes it the ideal solution for pumps that don’t run continuously, think engine cooling, and ballast systems. When you’re ready to go, your Johnson Pump Marine impeller will be too.

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Real-World Benefits for Builders and Boaters Alike

Whether you're specifying components as an OEM or managing maintenance as a boat owner, MC97 gives you the upper hand.

  • Consistent Performance
  • MC97 maintains its shape and flow characteristics across varying duty cycles, no swelling, no surprises.
  • Fewer Failures
  • Less deformation means less friction and wear, resulting in fewer impeller changes and reduced risk of pump damage.
  • Optimized Fit
  • Every impeller is engineered to match Johnson Pump Marine’s original equipment standards, delivering perfect alignment with our pumps.
  • Proven Durability
  • Reduced material fatigue and improved resilience make MC97 a smart investment in uptime and reliability.

Built for the Demands of the Marine Industry

As access becomes more and more limited in today’s engine compartments, a failed pump can mean costly downtime or warranty claims. OEMs and boat builders need components that perform under pressure, literally and figuratively.

Johnson Pump Marine designs, tests, and manufactures every impeller to perform as part of a system, not just as a standalone part. We own the rubber formulation, the impeller design, and the pump that powers it. That level of control means we can promise, and deliver, reliability across a wide range of marine applications.

Yanmar Customer Facility

A Deeper Dive: Engineering Beyond Theory

When it comes to flexible impeller pumps, real-world performance goes beyond theoretical flow rates. Flexible impeller systems must account for factors like suction lift, fluid temperature, and inlet pressure, all of which impact performance.

That’s why every Johnson Pump Marine specification is tested and validated against OEM requirements, not just design targets. Our development process ensures pumps meet required flow and head pressure at a defined engine RPM, maintaining performance even under unpredictable operating conditions.

Need perspective?

Our largest impeller, the F95, can move enough water to fill five bathtubs every minute, around 200 gallons (about 750 liters). And at 4,000 RPM, an F75 MC97 impeller completes 240,000 revolutions per hour. Over 100 hours, that’s 24 million revolutions, all while resisting deformation and maintaining flow. That’s durability in action.

Backed by SPX FLOW. Trusted by Builders. Proven by Boaters.

Whether you’re building an engine, rigging a new hull, or prepping for your next offshore run, the pump shouldn’t be the weak link in your system. Johnson Pump Marine impellers with MC97 give you the reliability you expect and the performance your equipment deserves.

Frequently Asked Questions

 

MC97 is a proprietary rubber compound developed by Johnson Pump Marine. Unlike traditional neoprene, MC97 resists water absorption, so it doesn’t swell during downtime. This prevents deformation, reduces wear, and ensures longer-lasting impeller performance.

 

 

Yes, MC97 impellers are recommended over Neoprene impellers in applications with intermittent use. Contact your SPX FLOW representative to confirm compatibility with your specific pump model.

 

 

Not at all. While MC97 is ideal for applications with intermittent use, it’s also effective in a wide range of marine systems, including ballast and genset cooling. For continuous-use commercial engines, our custom-formulated neoprene impellers can serve as a reliable alternative to MC97.

 

 

In many cases, yes. Because MC97 impellers are more resistant to swelling and degradation, they often outlast traditional neoprene impellers, especially in vessels that aren’t run daily.

 

 

Both materials are high-performing, but for continuously running systems, neoprene is still a proven option. MC97 shines in systems where idle time would otherwise cause neoprene to swell or take a compression set.

 

 

MC97 impellers follow the same maintenance schedule as standard impellers. However, due to their durability, they may require fewer replacements over time.

 

 

MC97 is optimized for raw water and seawater cooling applications. For specialized chemical compatibility, consult the pump and impeller datasheet or speak with an SPX FLOW technical advisor.

 

 

Use our Where to Buy tool to find authorized dealers and retailers. 

 

 

MC97 is available for most current models up to F75 and select legacy products. Contact us to verify availability for your specific application.

 

 

Yes, Johnson Pump Marine offers MC97 impellers designed to fit many competitive pump models. Contact us to find out if we have an MC97 impeller compatible with your specific pump.