WaterDog Outboard Savers

06/05/2026

How much water reaches the thermostat with flush muffs? Is it safe?

As far as I know, I am the first person to perform these experiments. I have not been able to find this data anywhere. I have been anticipating these results for quite some time, and I have to say I was surprised.

Rather than give you my conclusion, I wanted to show you the data first so we can think about it together. I welcome any comments, questions, or theories.

The clear plastic tube is connected to the thermostat housing with the thermostat removed so we can measure the flow reaching the top of the engine.

I used the flush port to prime the system before starting the motor, then turned the flush port off so we could observe flow with the muffs alone. In the video, you'll see how much water reaches the thermostat housing on the muffs compared to running the engine submerged in a tote.

To better understand the results, I also measured flow through the lower unit, telltale, and thermostat housing while supplying different known volumes of water through the pickup tube using a flow meter.

Using those measurements, we were able to estimate the impeller flow rate at idle.

Do you have a guess how much water the impeller is moving at idle?

06/03/2026

Why do I care so much about flushing? Because heat kills engines. Our anode is really about keeping your engine running cool, indefinitely.

Most mechanics understand that excessive heat damages engines, but many boat owners don't realize there are two major causes of heat-related wear beyond a failed impeller: corrosion impaired cooling systems and improper flushing.

When an engine is run on the flush port while running, water can leave through the pickup tube instead of fully filling the cooling system the way it does when the lower unit is submerged and operating normally. The pump is designed to squeeze water into the motor, it cannot squeeze air the same way because it easily compresses.

Over time, running on the flush port can lead to added piston ring and cylinder wall wear. If you flush your engine for 15 minutes for every 3 hours of run time, by the time you hit a thousand hours you will have 83 hours of flush time on the engine. You don't want to be running the motor dry during that time.

Unlike a broken part, heat damage happens slowly. As temperatures increase, metal expands more than intended, accelerating wear between the piston rings and cylinder walls. Over time this can contribute to blow-by, reduced sealing efficiency, and compression loss, it's hard to notice because it happens slowly.

All engines lose compression eventually. The question is how quickly.

Most outboards eventually have a corrosion filled cooling system and overheat. Keeping a clean cooling system removes heat more effectively, helping the engine stay within its designed operating temperature range. Less heat means less thermal expansion, less wear, and longer-lasting performance.

That's why we focus on flushing habits. Our goal is for your motor to retain performance as long as possible, that means efficient cooling while underway, and flushing properly.

A WaterDog Thermostat Abode prevents corrosion deposits from forming inside the cooling system, allowing the engine to maintain cooling efficiency, so it can keep its performance for years to come.

▪️ Protect the cooling system
▪️ Protect performance
▪️ Extend engine life

We Corrode, So Engines Don't! Long live all motors.

Orders shipped daily. 🇺🇸💪

06/02/2026

This is the biggest fear of an outboard thermostat housing failure... In this video you can see what happens to an engine when it hydro locks. That means water gets sucked into the intake and water doesn't compress the way that air does so as the Piston approaches the head either the head has to give or the rod has to bend and so the connecting rod bends, sometimes can throw a hole in the block.

On an outboard when water starts to leak out of the thermostat housing, it sprays into the cowling, some of that water can begin getting sucked into the intake and if the leak is bad enough in the proper place you can end up hydro locking the motor.

If you ever have held a connecting rod in your hand you know how Stout they are it's hard to imagine how much force would need to be created to do this but it does happen.

06/02/2026

What happens when you run without a thermostat? Taking measurements for the tote vs muffs comparison.

I wanted to get a reading of how much water through the thermostat housing with the thermostat removed given the volume of my hose. This way we can compare how much water flows through the thermostat housing / tell tale when the engine is running in the tote, we should be able to get a rough estimation of the actual volume produced by the impeller at idle.

We can then compare how much water comes through the thermostat housing with the flush muffs vs flush port, and then comparing all those volumes we can finally lay to rest the best flushing habits. I'm excited to try to see the volume produced at idle but also to find out if the impeller actually can push water back up the pick up-tube when running on the flush Port like some people think. I can argue that both ways so I'm interested to see the results.

One thing that I'm still trying to sort out, and I'm hoping that one of the master techs out there knows the answer.... If you run without the thermostat, does the tube leading to the lower part of the block bypass the exhaust guide and power head exhaust? Will it over cool the block while overheating the exhaust or is the exhaust over cooled as well?

I measured in this demonstration that 30% of the water is coming through the thermostat housing. Under normal operation that would run down the tube outside of the engine into the lower part of the block leading to the riser but I'm not sure if It bypasses the exhaust guides or not. But All the areas that it does bypass are getting 30% less water flow, gets to the riser it's cooler than it would have been.

Certainly, running without the thermostat excessively cools the motor, but does it overheat the exhaust guides as well? Will the flush muffs flow enough water through the thermostat housing? To be determined.

06/01/2026

We had a commercial fleet place an order this weekend and I'm excited to see how much they benefit from the WaterDog Anode.

This fleet operates 52 outboard motors, many of which accumulate between 2,000 and 3,000 hours per year. Some of their boats run 24-hour charters and can see 100-hour services multiple times in a single week!

What excites me isn't just the robust data we'll collect. It's the fact that another fleet looked at the anode, understood the problem we're trying to solve, and decided it was worth installing across their operation.
This fleet manager told me that historically they expected around 6,000 hours from these engines. It will be interesting to see how drastically corrosion mitigation can affect the life expectancy of these motors.

These boats accumulate operating hours so quickly that they'll generate years worth of data in a fraction of the time it would take the average recreational boater. And under their specific operating conditions it will really put our anode to the test and that is exciting.

It's only a matter a time before it's in your motor, hopefully before you have to replace it.

Protect What Powers You. We Corrode, So Engines Don't! 💪🇺🇸

I didn't have a good picture for this so I'm uploading my beautiful gardening partner Cali girl 😍.

06/01/2026

Is a regularly descaled motor still corroding? If a car has clean rims does that mean the breaks aren't working?

As we know, "scale" is the result of internal engine corrosion, it is the visible effect of the galvanic cell at work in the cooling system. You can clean it after it forms, or provide a more reactive metal to sacrifice itself.

Descaling the motor removes the effect but does not stop the cause which is why the pits are exposed.

Acid flushing restores cooling efficiency by removing the corrosion byproducts and minerals. That's a good thing, but it's not stopping the corrosion deposits or the pits from forming.

Cleaning the deposits is not the same as preventing the corrosion from affecting the engine metal with our anode.

Waterdogs thermostat anode is designed to stop corrosion deposits from forming in the cooling passages by providing Sacraficial material directly where the corrosion is initiated. Rather than protecting you from the effect of corrosion, we provide a replaceable component that actively corrodes before your engine does. The deposits will form on the anode, not in your engine.

You can see in this photo, the substance that flushes out of the motors is extremely metallic. After collecting the sample, it becomes extremely clear that it's not composed of salt and must be metal from the engine itself, it's the material from the pits in the metal. It will either lead to overheating if it's not clean, or eventually will form a hole.

With a simple 5 minute anode installation you can change where Corrosion is happening in your motor.

Instead of allowing corrosion to consume the engine and it components, provide a sacraficial component designed to be replaced during normal thermostat service.

Instead of cleaning your cooling system AFTER the corrosion clogs it, chose to keep it cleaner from the start.

We Corrode, So Engines Don't! 🇺🇸 Orders Shipped Daily.

WaterDog's Thermostat Anode stops all corrosion created by electrolysis at the thermostat. The only marine-grade Anti-Corrosion solution your engine ever needs!

05/31/2026

A clean motor is a cool motor, and a cool motor lives longer.

Most outboard motors don't die because someone forgot to change the oil. They slowly lose cooling efficiency over years of corrosion and deposit buildup inside the cooling system. This can be compounded by improper flushing habits.

As deposits accumulate inside the water jackets, heat transfer becomes less efficient. The engine gradually runs hotter, and over time that can contribute to warped heads, damaged gaskets, compression loss, and other expensive failures.

When an engine runs hotter than it should, the piston rings become less effective at sealing the combustion chamber. That means some of the energy that should be pushing the piston down ends up escaping past the rings as blow-by instead. Over time, performance suffers and compression can be lost.

That's why I'm always talking about proper flushing habits.

Flushing is important, but flushing alone cannot stop corrosion and deposits from forming inside the cooling system. In some cases, improper flushing habits can contribute to the same long-term performance loss that a compromised cooling system can cause.

The WaterDog Thermostat Anode helps protect the cooling system from corrosion and buildup before it becomes a problem. The result is a cleaner cooling system, more efficient heat transfer, and better long-term performance.

Most people think the biggest benefit is preventing corrosion holes but everyone benefits from a cleaner cooling passages.

The biggest benefit is keeping the cooling system clean so your engine can continue running at the temperatures it was designed to run at, year after year.

A clean motor is a cool motor, a cool motor keeps its performance and a motor that keeps its performance lives longer.

We Corrode, So Engines Don't. Protect What Powers You.

Orders Shipped Daily 🇺🇸🇺🇸💪💪

05/30/2026

Doesn't the impeller push the water up the pickup tube when I start it on the flush port? Why not?

When flushing the engine the impeller stops water from escaping if it's stationary, it allows the engine to fill with water properly. This is the recommended flushing technique, but when the engine is started things change.

Manufacturers do not recommend running on the flush port and we can now see why. You can see in the video, once started, the impeller begins to move the water over the hole in the impeller base and that allows water to exit the pickup grate where water normally enters.

This is because the impeller is not a centrifugal pump but it's a positive displacement pump and its off centered design is to throw water up the pick up tube when submerged. It is not designed to reverse the flow of water from the pickup tube, it cannot prime itself without water flowing towards the extended side or it being submerged.

This is the reason why the manufacturers tell you not to run on the flush port. You are essentially running the engine dry which is causing excess thermal wear on the engine.

Thermal wear is the enemy of the Marine engines and reducing it is the number one way to extend their life. We do that through proper maintenance on the cooling jacket with our anode and proper flushing habits after we take the boat out.

05/29/2026

The impeller is fully wet when running on the flush port, but is that really the concern?

The most common thing people talk about with flush port flushing is whether the impeller is running dry or not. As you can see in this video, trimmed up or trimmed down, the impeller is not dry, so why does the manufacturer recommend not running it?

Look at how little water is coming out around the exhaust riser, what does that mean?

This engine can hold about 1.6 gallons of water but has corrosion buildup, a clean engine may be closer to 1.8 – 2 gallons (please reach out if you'd like to measure a 4.2). The water leaving the engine is restricted by the small drain holes around the riser.

In multiple tests, the drain rate was about 2.4 gallons per minute. Majority of that water comes out around the riser, not the pickup tube, and it takes roughly 40 seconds to drain.

But when I run water through the flush port, most of the water appears to come straight out of the pickup tube and very little comes out around the riser.

That tells us the flush port and pickup tube have a low resistance flow path between them. The flush port feeds into the valley area of the engine, where water can split toward the thermostats and auxiliary cooling loop. But when the engine is being flushed from the port, gravity and path of least resistance allow much of that water to flow down toward the pickup tube.

Now here is the interesting part....

With the lower unit installed and the engine OFF, the stationary impeller acts like a restriction from water flowing out of the pickup tube. That allows the engine to fill on the flush port when it's OFF. We know that from previous experiments.

Now the question becomes, what happens when you start the engine?

The impeller is getting wet, but what is happening to the water flowing through the pickup tube? Can there be water in the engine?

05/29/2026

Brand new engine, 14 hours. Brand new components. Brand new anodes. Same old corrosion.

From the very first moment water begins flowing through an outboard engine, the galvanic cell is activated and metal begins dissolving into the cooling system.

Many people believe that regularly replacing factory anodes will stop corrosion. As you can plainly see, deposits are already forming throughout this powerhead after only 14 hours of operation, despite being properly maintained and flushed.

This particular engine was ultimately replaced under warranty for an issue unrelated to corrosion. However, the photos provide a great demonstration that corrosion begins immediately and is largely a consequence of the cooling system design, not owner neglect.

If you don't want your engine corroding, the solution is simple.

Install a WaterDog thermostat anode.

It corrodes first, so your engine doesn't.