Reports of Substantial Corrosion In Mercury Verado Motor Gear Case

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Author Topic:   Reports of Substantial Corrosion In Mercury Verado Motor Gear Case

djtdmd posted 06-26-2010 12:19 AM ET (US)
My factory installed twin 150 Verado's on my 255 Conquest have been found to have internal corrosion inside both lower units. They are both 6 months out if warranty. My Whaler techs and Verado certified techs found the corrosion when they changed the water impellers a few months ago. They showed me the metal wall that separates the water and exhaust that was all pitted and not flush at the top. I started to have a overheating problem last fall, and I wonder if this coincides with the corrosion that was found. The corrosion really irks me because I take excellent care of the motors: all recommended maintenence yearly, including new zincs; motors flushed after every trip. I do mostly saltwater fishing trips. Boat is used six months a year in New Jersey, then dry docked and shrink wrapped for the winter. My local Merc rep says it's out of warranty, call Mercury customer service, which I did. [Mercury customer service] are requesting my dealer take some photos and call them. We'll see what happens.
I am really upset that these engines are supposesly the best, and they [had] such good care. I am the only guy on my dock who flushed the engines after each trip, just to avoid this very senario! The corrosion was definitely there in August, when my warranty expired.
I would love to hear any comments from other Verado owners who may have had similar problems [with substantial corrosion in the wall between the water pump and exhaust passage in the gear case of a Mercury Verado outboard motor]. I really hope Mercury stand by their product. Three years out of a lower unit is ridiculous! Thanks for any input from you guys.--Dan
jimh posted 06-26-2010 06:15 AM ET (US)
I do not recall any other mentions of unusual corrosion in a Mercury gear case associated with a VERADO engine.
Jefecinco posted 06-26-2010 10:10 AM ET (US)
From postings all around the web my impression is that Mercury has been good about taking care of or helping with some issues on newly out of warranty Verados.
It's probably a little soon to go public.
Butch
fishgutz posted 06-26-2010 10:12 AM ET (US)
Funny, most if not all dry stack marinas on saltwater do not flush motors after every use. I wonder if flushing isn't a good idea. If flushing was necessary to prevent corrosion then these motors would be corroding away at a rather fast pace.
Tohsgib posted 06-26-2010 11:04 AM ET (US)
I see that all the time with Mercruiser outdrives. Nothing a little JB-Weld won't cure. Heat will corrode metal much more quicker in salt water, hence why you see it in outdrives which run hotter than outboards.
jimh posted 06-26-2010 11:06 AM ET (US)
Unusual corrosion may be due to galvanic corrosion, which has been accelerated by a small electrical leakage current in the outboard motor. An unnoticed path for positive battery current to flow or connect to a metallic component in contact with sea water can be the source of unusually fast galvanic corrosion. A low leakage current, too small to blow a fuse or cause noticeable battery discharge, could create accelerated galvanic corrosion.
Jefecinco posted 06-26-2010 07:49 PM ET (US)
An early sign of galvanic corrosion can be dulling of stainless steel propellers. The dulling is caused by the less noble aluminum plating onto the much more noble stainless steel. Perhaps newer outboard engine designs take preventive measures so this wont happen but I've seen it older engines.
Butch
jimh posted 06-27-2010 10:13 AM ET (US)
Nick--Your observation that the corrosion was accelerated by heat fits perfectly with the description of the location of the corrosion in this Mercury VERADO motor:
"...the metal wall that separates the water and exhaust that was all pitted and not flush at the top."
In outboard motors the usual practice is to direct cooling water into the exhaust passages from the power head downward through the mid-section and into the gear case in order to reduce the temperature of the exhaust system.
A corollary problem from hot exhaust temperature is failure of the propeller hub, particularly on propellers with thermoplastic hub inserts, due to the exhaust temperature exceeding the melting point of the thermoplastic, or at least rising above the point where the thermoplastic loses its strength and rigidity.
In the 150-HP Verado motors which have this corrosion problem, was there any problem with propeller hubs failing from high temperature exhaust?

jimh posted 06-27-2010 10:18 AM ET (US)
I also observe that if the corrosion has been caused by high temperature in the exhaust system, no amount of flushing with fresh water would really affect the corrosion. The corrosion would occur while the engine is running and there are high temperatures in the exhaust passage. Subsequent rinsing with fresh water would probably not reduce the corrosion that occurred when the hot saltwater and exhaust gas mixture was passing through the gear case.
Plotman posted 06-27-2010 10:50 AM ET (US)
It may have nothing to do with how the motors are made, and in fact may not be Mercury's fault at all. Friends have a slip where it was found that a short from the dock's shore power was leaking into the water. Caused horrible galvanic corrosion problems, but those were hardly the fault of the motor. They only figured it out when it was discovered that three adjacent boats all had similar problems.
The fact that both of your motors are having similar problems leads one to believe that you have some kind of electrical leak somewhere.
djtdmd posted 06-27-2010 10:12 PM ET (US)
My dock does not have shore power, and no other engines on other boats in the marina have had a problem like this. My Whaler dealership, where I have a slip, says they have never seen a problem like this on a 3-1/2-year-old engine. I will say that I typically would run the boat at WOT or close to it on the last five minutes channel to my marina, then slowing to no wake, then flushing when back at the marina. This should not be a problem since up until the last couple of months, the engines never overheated, and I know from Mercury that when they tested the Verado during its five year development, they ran the Verado at WOT for something like 1,000 straight hours, stopping only to change the oil. The outside of the Verado lower unit has no corrosion whatsoever. They put Verado motors on Reggie Fountain's racing boats, so I'm sure the engines should be able to handle a few minutes of opening them up--cut me a break! Besides, Mercury SmartCraft system would automatically limit [engine speed] if any damage to the engine could occur. This must be a Mercury [problem]. I have one of the first-year first-generation Verado motors made. They now have a five-year warranty, which includes five years [warranty against] corrosion! What has changed on the engine design that they would now have so much confidence in the engine's corrosion resistance?
Plotman posted 06-27-2010 11:11 PM ET (US)
Then there is likely some stray current issue with your boat's own electrical system. Get out a fluke and start checking for current.
jimh posted 06-28-2010 08:44 AM ET (US)
I would not make an inference that something actually changed in the design of the Mercury VERADO engine or in its manufacturing quality solely because the warranty period of a new engine increased to five years from three years. Often the warranty period offered on an engine is adjusted to match warranty offers or promotions being made by competitors in order to maintain an equal position in the new engine marketplace.
So far we have two distinct theories on the cause of the corrosion in the gear case of the Mercury VERADO: a defect in manufacture, or a result of unusual environment. Because both engines have shown the same problem, we can use that to make a judgement about the cause.
If the corrosion is due to a defect in the engine, then we have to assume that the defect occurred in both engines. The defect could either be due to an error in the manufacturing, that is a mistake made during the process, or the corrosion could be due to an inherent defect in the design. In modern manufacturing the rate of defects due to error in assembly is really quite low, usually only a few percent. It would be unusual to have two engines which both have a defect due to an error in manufacturing, if the error were totally random in its occurrence. This tends to disfavor the theory that the defect is due to an error in manufacturing, although it does not rule out that cause.
On the other hand, if the defect were inherent in the design, then it would be quite normal that both engines would have the defect. However, so would many other engines of the same epoch of design and manufacture. We do not see that corrosion of the wall separating the exhaust passage of the gear case of a 150-HP VERADO motor is a problem that has occurred with great frequency among all 150-HP VERADO motors, so this tends to disfavor the theory that the cause is a defect in design.
If the defect were due to environmental conditions, it is quite reasonable that the defect would manifest in both engines, because they were operated in the same environment. We can now look to the source of the environmental condition that causes the corrosion. Since the boat likely spends most of its time at the dock, the dock and surrounding marina facilities are important environmental influences. However, it would be likely that other boats in that environment could be affected. We do not know if other VERADO 150-HP engines are in the same marina. If there were other VERADO 150-HP engines with this corrosion in the same marina, it would be indicative of a problem with the marina. Next we turn to the most local of environments, the boat itself. It could be that there are conditions unique to the boat and installation of these motors that have caused the corrosion.
Jefecinco posted 06-28-2010 09:49 AM ET (US)
The possibility remains that the next door boat could be the culprit. Get a half cell and check the water in and around your slip or have it done.
Your dock has no shore power, OK, but does it have any electrical power for battery charging, etc? Does it have lighting for night use? Any power at all can create stray current which can be a disaster for aluminum outdrives and lower units. Even if there is wiring on the dock without an outlet stray current is possible.
Checking with a half cell will put any stray current concerns to rest. If stray current is present it can be isolated and corrected.
A properly managed marina often conducts stray current measurements in all slips periodically.
Butch
Tohsgib posted 06-28-2010 11:26 AM ET (US)
If your neighbor is using a battery charger to keep his livewell going....viola!
hauptjm posted 06-28-2010 12:27 PM ET (US)
Just a thought: I would assume the motors would be tilted free of the water during rested state. Since, the occurance of galvanic corrosion would require the motors to be exposed to the electrical current present in the surrounding water, and assuming the motors are tilted completely free from the water, how could electrolysis be the culprit?
Now if the motors are kept in the water during these long periods of idle time, then...
Am I missing something?
jimh posted 06-30-2010 09:18 AM ET (US)
The observation that the most likely method of storing the motors when not in use would involve tilting them clear of the water is a very cogent point in this discussion. With the motors out of the water, the potential for galvanic corrosion due to leakage current in the marina is much less.
If we disqualify galvanic corrosion as the cause of the substantial corrosion in the gear case of the Mercury VERADO motor where the wall between the exhaust passage and adjoining areas has been thinned, we again have to return to the notion that the corrosion occurred due to high temperature saltwater and exhaust gases running through the exhaust passage.
There is also this interesting statement:
"I started to have a overheating problem last fall, and I wonder if this coincides with the corrosion that was found."
Overheating probably means reduced flow of cooling water, including reduced flow of cooling water in the exhaust passages. It also seems reasonable that if there is reduced water flow and higher engine temperatures, then the temperature in the exhaust passages would also tend to be higher. I think there is a plausible link between problems with corrosion in this Mercury Verado motor exhaust passages and problems with overheating of the engine.
We are now four days into this discussion and I am surprised that we have not had any replies from any other owners of a Mercury Verado motor who have experienced this problem. While I would not say that this is conclusive proof that no one else has the problem, I think there are enough Verado owners reading this that if the problem were widespread we would have heard from someone by now.
hauptjm posted 06-30-2010 11:34 AM ET (US)
So, if the Marina has been eliminated (unexposed motors to galvanic corrosion) and manufacturer defect has been eliminated (lack of corroboration), something else seems to be happening here. The chance that two motors, on the same boat, have this odd occurence of defect that simultaneously started perhaps a year ago in the form of over-heating, that resulted in the internal corrosion is highly unlikely. Something else is occuring.
Granted, the electolysis theory would have been my first thought. djtdmd, what other factors are we missing?
Buckda posted 06-30-2010 12:05 PM ET (US)
I don't think the environment "at his slip" has been eliminated. He has not yet reported back about the possibility of a neighboring vessel charging batteries or running a live well, nor have we eliminated electrolysis due to stray current through a reported practice of tilting the motors free of the water.
I would be interested to see if these were sequentially manufactured motors. I believe that to be very unlikely, however, IF there was a problem with a manufacturing defect, it would be most likely that it would occur with motors that were manufactured under extremely similar circumstances - i.e. the same day/hour - with the same materials, personnel, etc., right?
Right now, we KNOW from reports on this board that were corroborated with photographic evidence, that there have been Mercury motor(s) released from the factory with finish paint, but NO primer. That would be a critical protective element in a highly corrosive environment such as a water jacket.
hauptjm posted 06-30-2010 03:16 PM ET (US)
Buckda, are you saying that if he does, in fact leaves his motors tilted and free of the surrounding water, the electrolysis problem could still occur? I assumed that the lower units would have to be "exposed" to the stray current (charger, livewell, etc.) to be negatively affected.
Buckda posted 06-30-2010 03:20 PM ET (US)
No, I'm saying we don't know what his practice is regarding tilting the engines or not. Until we know that, we can't rule out stray electrical current at his slip with the information we DO have.
All we know is that there is corrosion on both engines. If the engines are "in" the water, then they are subject to potential stray current corrosion. If they are tilted free, the likelihood of this type of corrosion happening at his slip due to stray currents is approaching zero, right?
Buckda posted 06-30-2010 03:22 PM ET (US)
Maybe they got struck by lightning.
:|
/obscure reference to very old thread.
L H G posted 06-30-2010 05:12 PM ET (US)
[Changed TOPIC. Please contact the moderator via email to discuss that topic.--jimh]
Plotman posted 06-30-2010 08:33 PM ET (US)
[Responded to L H G's new topic. Contact L H G via email to discuss that topic.--jimh]
ScottS posted 06-30-2010 08:47 PM ET (US)
Even if the motor is tilted up doesn't the bottom of the outboard mounting bracket still contact the water? It has on every boat I've owned. Therefore, couldn't electrical current still occur through the bracket and be a possible cause? Does the dock have lights, an illuminated sign, or any other kind of electrical device? Electrical current in the water near a dock is a common occurance. That's why you should never swim near a marina dock (besides the chance of a boat running you over).
ScottS
jimh posted 06-30-2010 08:57 PM ET (US)
Scott--You should try an experiment with the same chemistry as involved in galvanic corrosion. Put a metal into an electrolyte solution, and apply a current. See if any electro-plating of the metal occurs in regions of the metal that were not immersed in the electrolyte solution.
jimh posted 06-30-2010 11:04 PM ET (US)
One factor not mentioned in the discussion is the age of these motors. They are 3-1/2-years old. I do not recall precisely when the 150-HP model of VERADO was first introduced, but I suspect that it was not more than four years ago. This makes these two 150-HP Verado motors perhaps two of the older 150-HP Verado motors out there.
I also get the impression that these motors might have somewhat more hour of running time on them than the typical 60-hour-per-year user. The mention that the owner "[does] mostly saltwater fishing trips," seems like it might mean a lot of long runs offshore.
If these are two of the older and higher hour 150-HP Verado motors, the appearance of this corrosion in the gear case that has reduced the wall thickness of the exhaust passage could be an early report or early sign of the problem, and we may not have any other corroborating reports simply because there are not as many 150-HP motors of this age and running time.
I did find an interesting comment on corrosion failures in the gear case of other Verado motors, but they were the 275-HP motors. To any Verado expert reading this thread, I have to ask: is the gear case on a 150-HP Verado the same as the gear case used on the six-cylinder Verado motors?
hauptjm posted 06-30-2010 11:07 PM ET (US)
I thought of Scott's proposition earlier, but came away with the same conclusion: the bracket would be eaten away, not the internal workings if the lower portion of the motor. At least not until visable damage was done to the bracket. Since damage to the bracket wasn't mentioned, I assume it's not present.
djtdmd posted 07-01-2010 08:42 AM ET (US)
Interesting what Jimh said, as I may have mentioned, I have exactly 400hrs now on the engines. These are the first Verado's made, not sure if they changed anything with the new generation 2 models. Interestingly, I saw the inside of a optimax yesterday, and the exhaust chamber walls were plastic, not aluminum, like my Verado. This makes a whole lot more sense to me as a non- metal can't corrode like metal. Still waiting for Merc on this one....

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Author	Topic: Reports of Substantial Corrosion In Mercury Verado Motor Gear Case
djtdmd	posted 06-26-2010 12:19 AM ET (US) My factory installed twin 150 Verado's on my 255 Conquest have been found to have internal corrosion inside both lower units. They are both 6 months out if warranty. My Whaler techs and Verado certified techs found the corrosion when they changed the water impellers a few months ago. They showed me the metal wall that separates the water and exhaust that was all pitted and not flush at the top. I started to have a overheating problem last fall, and I wonder if this coincides with the corrosion that was found. The corrosion really irks me because I take excellent care of the motors: all recommended maintenence yearly, including new zincs; motors flushed after every trip. I do mostly saltwater fishing trips. Boat is used six months a year in New Jersey, then dry docked and shrink wrapped for the winter. My local Merc rep says it's out of warranty, call Mercury customer service, which I did. [Mercury customer service] are requesting my dealer take some photos and call them. We'll see what happens. I am really upset that these engines are supposesly the best, and they [had] such good care. I am the only guy on my dock who flushed the engines after each trip, just to avoid this very senario! The corrosion was definitely there in August, when my warranty expired. I would love to hear any comments from other Verado owners who may have had similar problems [with substantial corrosion in the wall between the water pump and exhaust passage in the gear case of a Mercury Verado outboard motor]. I really hope Mercury stand by their product. Three years out of a lower unit is ridiculous! Thanks for any input from you guys.--Dan
jimh	posted 06-26-2010 06:15 AM ET (US) I do not recall any other mentions of unusual corrosion in a Mercury gear case associated with a VERADO engine.
Jefecinco	posted 06-26-2010 10:10 AM ET (US) From postings all around the web my impression is that Mercury has been good about taking care of or helping with some issues on newly out of warranty Verados. It's probably a little soon to go public. Butch
fishgutz	posted 06-26-2010 10:12 AM ET (US) Funny, most if not all dry stack marinas on saltwater do not flush motors after every use. I wonder if flushing isn't a good idea. If flushing was necessary to prevent corrosion then these motors would be corroding away at a rather fast pace.
Tohsgib	posted 06-26-2010 11:04 AM ET (US) I see that all the time with Mercruiser outdrives. Nothing a little JB-Weld won't cure. Heat will corrode metal much more quicker in salt water, hence why you see it in outdrives which run hotter than outboards.
jimh	posted 06-26-2010 11:06 AM ET (US) Unusual corrosion may be due to galvanic corrosion, which has been accelerated by a small electrical leakage current in the outboard motor. An unnoticed path for positive battery current to flow or connect to a metallic component in contact with sea water can be the source of unusually fast galvanic corrosion. A low leakage current, too small to blow a fuse or cause noticeable battery discharge, could create accelerated galvanic corrosion.
Jefecinco	posted 06-26-2010 07:49 PM ET (US) An early sign of galvanic corrosion can be dulling of stainless steel propellers. The dulling is caused by the less noble aluminum plating onto the much more noble stainless steel. Perhaps newer outboard engine designs take preventive measures so this wont happen but I've seen it older engines. Butch
jimh	posted 06-27-2010 10:13 AM ET (US) Nick--Your observation that the corrosion was accelerated by heat fits perfectly with the description of the location of the corrosion in this Mercury VERADO motor: "...the metal wall that separates the water and exhaust that was all pitted and not flush at the top." In outboard motors the usual practice is to direct cooling water into the exhaust passages from the power head downward through the mid-section and into the gear case in order to reduce the temperature of the exhaust system. A corollary problem from hot exhaust temperature is failure of the propeller hub, particularly on propellers with thermoplastic hub inserts, due to the exhaust temperature exceeding the melting point of the thermoplastic, or at least rising above the point where the thermoplastic loses its strength and rigidity. In the 150-HP Verado motors which have this corrosion problem, was there any problem with propeller hubs failing from high temperature exhaust?
jimh	posted 06-27-2010 10:18 AM ET (US) I also observe that if the corrosion has been caused by high temperature in the exhaust system, no amount of flushing with fresh water would really affect the corrosion. The corrosion would occur while the engine is running and there are high temperatures in the exhaust passage. Subsequent rinsing with fresh water would probably not reduce the corrosion that occurred when the hot saltwater and exhaust gas mixture was passing through the gear case.
Plotman	posted 06-27-2010 10:50 AM ET (US) It may have nothing to do with how the motors are made, and in fact may not be Mercury's fault at all. Friends have a slip where it was found that a short from the dock's shore power was leaking into the water. Caused horrible galvanic corrosion problems, but those were hardly the fault of the motor. They only figured it out when it was discovered that three adjacent boats all had similar problems. The fact that both of your motors are having similar problems leads one to believe that you have some kind of electrical leak somewhere.
djtdmd	posted 06-27-2010 10:12 PM ET (US) My dock does not have shore power, and no other engines on other boats in the marina have had a problem like this. My Whaler dealership, where I have a slip, says they have never seen a problem like this on a 3-1/2-year-old engine. I will say that I typically would run the boat at WOT or close to it on the last five minutes channel to my marina, then slowing to no wake, then flushing when back at the marina. This should not be a problem since up until the last couple of months, the engines never overheated, and I know from Mercury that when they tested the Verado during its five year development, they ran the Verado at WOT for something like 1,000 straight hours, stopping only to change the oil. The outside of the Verado lower unit has no corrosion whatsoever. They put Verado motors on Reggie Fountain's racing boats, so I'm sure the engines should be able to handle a few minutes of opening them up--cut me a break! Besides, Mercury SmartCraft system would automatically limit [engine speed] if any damage to the engine could occur. This must be a Mercury [problem]. I have one of the first-year first-generation Verado motors made. They now have a five-year warranty, which includes five years [warranty against] corrosion! What has changed on the engine design that they would now have so much confidence in the engine's corrosion resistance?
Plotman	posted 06-27-2010 11:11 PM ET (US) Then there is likely some stray current issue with your boat's own electrical system. Get out a fluke and start checking for current.
jimh	posted 06-28-2010 08:44 AM ET (US) I would not make an inference that something actually changed in the design of the Mercury VERADO engine or in its manufacturing quality solely because the warranty period of a new engine increased to five years from three years. Often the warranty period offered on an engine is adjusted to match warranty offers or promotions being made by competitors in order to maintain an equal position in the new engine marketplace. So far we have two distinct theories on the cause of the corrosion in the gear case of the Mercury VERADO: a defect in manufacture, or a result of unusual environment. Because both engines have shown the same problem, we can use that to make a judgement about the cause. If the corrosion is due to a defect in the engine, then we have to assume that the defect occurred in both engines. The defect could either be due to an error in the manufacturing, that is a mistake made during the process, or the corrosion could be due to an inherent defect in the design. In modern manufacturing the rate of defects due to error in assembly is really quite low, usually only a few percent. It would be unusual to have two engines which both have a defect due to an error in manufacturing, if the error were totally random in its occurrence. This tends to disfavor the theory that the defect is due to an error in manufacturing, although it does not rule out that cause. On the other hand, if the defect were inherent in the design, then it would be quite normal that both engines would have the defect. However, so would many other engines of the same epoch of design and manufacture. We do not see that corrosion of the wall separating the exhaust passage of the gear case of a 150-HP VERADO motor is a problem that has occurred with great frequency among all 150-HP VERADO motors, so this tends to disfavor the theory that the cause is a defect in design. If the defect were due to environmental conditions, it is quite reasonable that the defect would manifest in both engines, because they were operated in the same environment. We can now look to the source of the environmental condition that causes the corrosion. Since the boat likely spends most of its time at the dock, the dock and surrounding marina facilities are important environmental influences. However, it would be likely that other boats in that environment could be affected. We do not know if other VERADO 150-HP engines are in the same marina. If there were other VERADO 150-HP engines with this corrosion in the same marina, it would be indicative of a problem with the marina. Next we turn to the most local of environments, the boat itself. It could be that there are conditions unique to the boat and installation of these motors that have caused the corrosion.
Jefecinco	posted 06-28-2010 09:49 AM ET (US) The possibility remains that the next door boat could be the culprit. Get a half cell and check the water in and around your slip or have it done. Your dock has no shore power, OK, but does it have any electrical power for battery charging, etc? Does it have lighting for night use? Any power at all can create stray current which can be a disaster for aluminum outdrives and lower units. Even if there is wiring on the dock without an outlet stray current is possible. Checking with a half cell will put any stray current concerns to rest. If stray current is present it can be isolated and corrected. A properly managed marina often conducts stray current measurements in all slips periodically. Butch
Tohsgib	posted 06-28-2010 11:26 AM ET (US) If your neighbor is using a battery charger to keep his livewell going....viola!
hauptjm	posted 06-28-2010 12:27 PM ET (US) Just a thought: I would assume the motors would be tilted free of the water during rested state. Since, the occurance of galvanic corrosion would require the motors to be exposed to the electrical current present in the surrounding water, and assuming the motors are tilted completely free from the water, how could electrolysis be the culprit? Now if the motors are kept in the water during these long periods of idle time, then... Am I missing something?
jimh	posted 06-30-2010 09:18 AM ET (US) The observation that the most likely method of storing the motors when not in use would involve tilting them clear of the water is a very cogent point in this discussion. With the motors out of the water, the potential for galvanic corrosion due to leakage current in the marina is much less. If we disqualify galvanic corrosion as the cause of the substantial corrosion in the gear case of the Mercury VERADO motor where the wall between the exhaust passage and adjoining areas has been thinned, we again have to return to the notion that the corrosion occurred due to high temperature saltwater and exhaust gases running through the exhaust passage. There is also this interesting statement: "I started to have a overheating problem last fall, and I wonder if this coincides with the corrosion that was found." Overheating probably means reduced flow of cooling water, including reduced flow of cooling water in the exhaust passages. It also seems reasonable that if there is reduced water flow and higher engine temperatures, then the temperature in the exhaust passages would also tend to be higher. I think there is a plausible link between problems with corrosion in this Mercury Verado motor exhaust passages and problems with overheating of the engine. We are now four days into this discussion and I am surprised that we have not had any replies from any other owners of a Mercury Verado motor who have experienced this problem. While I would not say that this is conclusive proof that no one else has the problem, I think there are enough Verado owners reading this that if the problem were widespread we would have heard from someone by now.
hauptjm	posted 06-30-2010 11:34 AM ET (US) So, if the Marina has been eliminated (unexposed motors to galvanic corrosion) and manufacturer defect has been eliminated (lack of corroboration), something else seems to be happening here. The chance that two motors, on the same boat, have this odd occurence of defect that simultaneously started perhaps a year ago in the form of over-heating, that resulted in the internal corrosion is highly unlikely. Something else is occuring. Granted, the electolysis theory would have been my first thought. djtdmd, what other factors are we missing?
Buckda	posted 06-30-2010 12:05 PM ET (US) I don't think the environment "at his slip" has been eliminated. He has not yet reported back about the possibility of a neighboring vessel charging batteries or running a live well, nor have we eliminated electrolysis due to stray current through a reported practice of tilting the motors free of the water. I would be interested to see if these were sequentially manufactured motors. I believe that to be very unlikely, however, IF there was a problem with a manufacturing defect, it would be most likely that it would occur with motors that were manufactured under extremely similar circumstances - i.e. the same day/hour - with the same materials, personnel, etc., right? Right now, we KNOW from reports on this board that were corroborated with photographic evidence, that there have been Mercury motor(s) released from the factory with finish paint, but NO primer. That would be a critical protective element in a highly corrosive environment such as a water jacket.
hauptjm	posted 06-30-2010 03:16 PM ET (US) Buckda, are you saying that if he does, in fact leaves his motors tilted and free of the surrounding water, the electrolysis problem could still occur? I assumed that the lower units would have to be "exposed" to the stray current (charger, livewell, etc.) to be negatively affected.
Buckda	posted 06-30-2010 03:20 PM ET (US) No, I'm saying we don't know what his practice is regarding tilting the engines or not. Until we know that, we can't rule out stray electrical current at his slip with the information we DO have. All we know is that there is corrosion on both engines. If the engines are "in" the water, then they are subject to potential stray current corrosion. If they are tilted free, the likelihood of this type of corrosion happening at his slip due to stray currents is approaching zero, right?
Buckda	posted 06-30-2010 03:22 PM ET (US) Maybe they got struck by lightning. :\| /obscure reference to very old thread.
L H G	posted 06-30-2010 05:12 PM ET (US) [Changed TOPIC. Please contact the moderator via email to discuss that topic.--jimh]
Plotman	posted 06-30-2010 08:33 PM ET (US) [Responded to L H G's new topic. Contact L H G via email to discuss that topic.--jimh]
ScottS	posted 06-30-2010 08:47 PM ET (US) Even if the motor is tilted up doesn't the bottom of the outboard mounting bracket still contact the water? It has on every boat I've owned. Therefore, couldn't electrical current still occur through the bracket and be a possible cause? Does the dock have lights, an illuminated sign, or any other kind of electrical device? Electrical current in the water near a dock is a common occurance. That's why you should never swim near a marina dock (besides the chance of a boat running you over). ScottS
jimh	posted 06-30-2010 08:57 PM ET (US) Scott--You should try an experiment with the same chemistry as involved in galvanic corrosion. Put a metal into an electrolyte solution, and apply a current. See if any electro-plating of the metal occurs in regions of the metal that were not immersed in the electrolyte solution.
jimh	posted 06-30-2010 11:04 PM ET (US) One factor not mentioned in the discussion is the age of these motors. They are 3-1/2-years old. I do not recall precisely when the 150-HP model of VERADO was first introduced, but I suspect that it was not more than four years ago. This makes these two 150-HP Verado motors perhaps two of the older 150-HP Verado motors out there. I also get the impression that these motors might have somewhat more hour of running time on them than the typical 60-hour-per-year user. The mention that the owner "[does] mostly saltwater fishing trips," seems like it might mean a lot of long runs offshore. If these are two of the older and higher hour 150-HP Verado motors, the appearance of this corrosion in the gear case that has reduced the wall thickness of the exhaust passage could be an early report or early sign of the problem, and we may not have any other corroborating reports simply because there are not as many 150-HP motors of this age and running time. I did find an interesting comment on corrosion failures in the gear case of other Verado motors, but they were the 275-HP motors. To any Verado expert reading this thread, I have to ask: is the gear case on a 150-HP Verado the same as the gear case used on the six-cylinder Verado motors?
hauptjm	posted 06-30-2010 11:07 PM ET (US) I thought of Scott's proposition earlier, but came away with the same conclusion: the bracket would be eaten away, not the internal workings if the lower portion of the motor. At least not until visable damage was done to the bracket. Since damage to the bracket wasn't mentioned, I assume it's not present.
djtdmd	posted 07-01-2010 08:42 AM ET (US) Interesting what Jimh said, as I may have mentioned, I have exactly 400hrs now on the engines. These are the first Verado's made, not sure if they changed anything with the new generation 2 models. Interestingly, I saw the inside of a optimax yesterday, and the exhaust chamber walls were plastic, not aluminum, like my Verado. This makes a whole lot more sense to me as a non- metal can't corrode like metal. Still waiting for Merc on this one....