Outboard Maintenance: Flushing with Freshwater After Saltwater Use

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Author Topic:   Outboard Maintenance: Flushing with Freshwater After Saltwater Use

ktm3ten posted 09-16-2010 09:46 PM ET (US)
What time interval or trip interval can one go without flushing [with freshwater] an outboard [that has been used in saltwater]? If run my boat for two days in saltwater before I flush it, is that [two day interval] a big deal? How about a week [of running in saltwater before flushing the engine with fresh water]? Does [the length of the time interval between flushing with freshwater] change if [boat use in saltwater] is irregular, [that is,] once or twice per year, [compared to] routine [use in saltwater]? Thanks
macfam posted 09-16-2010 10:08 PM ET (US)
Outboards were made to run in saltwater. There have been many outboards over mnay years that didn't get a frequent freshwater flush, and still lasted for many years.
If you can do it, great; if not, do it when you can.
crbenny posted 09-16-2010 10:14 PM ET (US)
In New England, we launch in May. The boat sits on her mooring through October without being flushed all season. This repeats year after year. There are boats in the bay where I grew up that have the same outboards on the transom as when I was a kid in the 70s.
My Outrage 18 has the original 1987 135 Mercury on the back. I flush it when I can with Salt-Away and perform general maintenance and that's it.
Don't worry about a few days or even a few weeks. Outboards are built for this environment and they're more corrosion resistant today that ever before. Flush when you can and enjoy.
Chris

Tohsgib posted 09-16-2010 10:32 PM ET (US)
Yeah, worry about it in 10-15 years. Go back north and flush if not convenient. What I do when I go to the Keys is I stop on Alligator alley and back it in to the fresh water and let it run on the trailer for a beer. DONE!
Destin_Dauntless posted 09-16-2010 11:35 PM ET (US)
Man, saltwater kills everything. I use salt-away and flush after every use. If I don't get it that day, I make sure to get to it the next. My house is 10 years old, the same as my whaler, and the metal entry lights over my door are falling apart from salt in the air.
Oh, and my tilt motor rusted on the back side against my transom where you couldn't see it on my 200 opti. That was a pain to fix.
PeteB88 posted 09-16-2010 11:36 PM ET (US)
I don't know why fresh water jockeys seem to worry so much about saltwater and their engines. "It's NEVER been in salt water." is what we hear all the time up here in the Land of Unsalted Seas. .Actually Unsalted is becoming a brand that I think started with Great Lakes surfers. As regards outboards and our boats they are indeed intended for salt water use. There must be 10s of thousands of them in service. Certainly corrosive environment is worrisome but so what? I know cats on both coasts that don't flush their boat motors.
elaelap posted 09-16-2010 11:52 PM ET (US)
I flush after every saltwater use, and wash down my boat and motors with fresh water as well. Doesn't take very long and can't hurt, so why not? But that's not really the topic question, is it? I don't know the answer, and I'm not sure anyone really does. Probably many other factors are involved: salinity of water, temperature and humidity, frequency of use, etc, etc.
Tony
tedious posted 09-17-2010 08:30 AM ET (US)
Exactly the same experience as Chris - our Maine boat goes in the saltwater in May, lives on a mooring and gets used all summer, and comes out in early October. The only flushing it ever gets is while we're fogging it for the winter.
Don't stress over a few days - sheesh.
Tim
jimh posted 09-17-2010 08:36 AM ET (US)
[This discussion of outboard maintenance has been moved to REPAIRS/MODS.]
jimh posted 09-17-2010 08:44 AM ET (US)
The effect of saltwater on an engine is likely influenced by the temperature of the water. I notice that comments from boaters in Maine, with cold saltwater, reveal a more casual attitude about flushing than you often see from boaters in areas with saltwater with tropical temperatures.
The combination of sun, heat, and saltwater in areas like south Florida probably create conditions of greater concern than you would find in Maine or in the northern Pacific coast.
hauptjm posted 09-17-2010 09:58 AM ET (US)
Where I keep my boat on the MS Gulf Coast, I have to travel about 15 minutes up a river and then 5 minutes through a bayou to get to my dock. All of this is beautiful, bronze fresh water. By the time I arrive at my dock, I'm fully flushed with fresh water. When I travel to other locales, I try to flush daily or every other day if I don't run the boat in fresh water.
weekendwarrior posted 09-17-2010 12:14 PM ET (US)
I am in S FL and in summer water temps are in the upper 80's (in the 90's in some areas) and air temps in the upper 90's with hot sun. Aside from the typical salt-induced corrosion (mostly bolts, just try to disassemble a block or lower unit after 10-15 years of salt use and no flushing or rinsing), the problem I have seen over the years is the salt water left in the motor dries up quickly (relatively) and leaves the salt behind. This salt is really hard and doesn't rinse out with just plain water, so over time it builds up and can eventually cause problems. If you use the motor often and it stays wet then it's not such a problem. But lots of people use it once every month or two. I am religious about flushing myself and after a couple years when I change my thermostat, it has hard salt chunks on it, so an unflushed motor here would surely be worse. Salt definitely builds up. If you use the boat daily the I wouldn't worry about flushing if it's a PITA, until you're ready to stop using it. Engine makers make a point of addressing flushing (my manual explicitly says flush after salt use) so I think it's important, but if it gets daily use then what's the point.
tedious posted 09-17-2010 12:17 PM ET (US)
Jim, one other thing to point out on the difference in flushing attitudes between casual Maine, and fussy Florida, is that a higher proportion of boats in Maine tend to be on moorings rather than in slips or at docks. The greater tidal range has a lot to do with that - it's quite expensive to build a setup that can support a boat properly through a 10 foot tidal range.
I would flush my motor more often if I had 1/4 mile of hose:-).
Tim
tom976 posted 09-17-2010 04:39 PM ET (US)
The previous owner of my boat had it moored. Maybe flushed it once a year. When I got it and had to pull one of the heads, I opened up the water jacket to see whats up while it was all apart.
WOW lots of salt in there. Thermostats were shot, internal anodes on my yamaha salt water series II had to be replaced. (motors a 1997, I got the boat in early 2009) This was a motor designed for the saltwater and still had some minor issues with salt water.
These days every time I come back to the dock I hook it up to water before I wash her down.
Tom
tedious posted 09-18-2010 09:33 AM ET (US)
I am not sure I'd consider having to replace the thermostats after 12 years all that unusual, regardless of how much flushing was done. And the cylinder head anodes should be checked every year as part of routine maintenance - we check ours every year, and usually replace them every third year.
Tim
contender posted 09-18-2010 10:16 AM ET (US)
You have to flush your engine after using it in salt water(if you want it to last) other wise the inside water jackets, thermostats and senders will malfunction. Once the water drains out of your engine (back home on the trailer) the salt remains, and not only does the salt remains but it starts to expand and clog the arteries of the engine. Salt is also a corrosive and the salt water running through an engine is like sand paper on the metal on the water jackets and other components inside. Its your choice.
Tohsgib posted 09-23-2010 12:07 PM ET (US)
I have [three older outboards] in my shed that are all saltwater engines and antiques. Maintenence is the key, not what the level of salinity.
Matt F posted 09-23-2010 01:49 PM ET (US)
Here in Mass, I can't think of anyone who flushes after every use. Boats go in in the late spring, come out around now and are flushed prior to being put to bed for the winter.
Come to think of it, I don't think I could flush it if I wanted. Spending fifteen minutes running the hose a the dock only to have to motor back out through the very same salt water to the mooring seems problematic....
jimh posted 09-24-2010 09:36 AM ET (US)
As a freshwater boater, I can acknowledge we perhaps hold the corrosive effects of saltwater in too much regard. Following the rare times I have used my boat in saltwater, I try to thoroughly flush the engine, the boat, and (most importantly) the trailer with freshwater. If I were an habitué of saltwater boating, I probably would not go overboard with flushing the internal cooling passages of the engine after every use.
edgarop posted 10-03-2010 08:11 PM ET (US)
I run my 1973 evinrude 115 out of the Sf bay area mostly Bodega bay and always flush it when i get home. i run it on the hose bib for 10 minutes. ive owned it for 5 years and never had a problem overheating. the only thing that ive dealt with is siezed water impeller bolts. broke them in the lower unit had to drill out and put some HELI coils in there.
Chuck Tribolet posted 10-04-2010 01:26 AM ET (US)
Salt (sodium chloride, NaCl) is highly soluble in water. If
there's something white in there that's not flushing out, it
ain't NaCl.

Chuck
(I flush my Evinrude 90 after every saltwater use. It's nicely
set up, in that I don't have to run it to flush it. There
are female hose threads at the back of the block, run water,
done. I takes about 1 minute of my time, about five minutes
elapsed, during which I'm either stowing stuff I took with
me or enjoying a brewski, or bot. I've got 1000 hours over
13 years, probably 800 days underway on saltwater.)
weekendwarrior posted 10-04-2010 07:38 AM ET (US)
Whatever it is, there's bunches of white chalky and chunky stuff in the passages and on the thermostat. I will try to remember to take some pictures next time I swap the thermostat.
I have tried to take a few old salt water engines apart, engines that were flushed, and always ended up with several bolts that were corroded, some of which just broke off before you even get any real torque on them.

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Author	Topic: Outboard Maintenance: Flushing with Freshwater After Saltwater Use
ktm3ten	posted 09-16-2010 09:46 PM ET (US) What time interval or trip interval can one go without flushing [with freshwater] an outboard [that has been used in saltwater]? If run my boat for two days in saltwater before I flush it, is that [two day interval] a big deal? How about a week [of running in saltwater before flushing the engine with fresh water]? Does [the length of the time interval between flushing with freshwater] change if [boat use in saltwater] is irregular, [that is,] once or twice per year, [compared to] routine [use in saltwater]? Thanks
macfam	posted 09-16-2010 10:08 PM ET (US) Outboards were made to run in saltwater. There have been many outboards over mnay years that didn't get a frequent freshwater flush, and still lasted for many years. If you can do it, great; if not, do it when you can.
crbenny	posted 09-16-2010 10:14 PM ET (US) In New England, we launch in May. The boat sits on her mooring through October without being flushed all season. This repeats year after year. There are boats in the bay where I grew up that have the same outboards on the transom as when I was a kid in the 70s. My Outrage 18 has the original 1987 135 Mercury on the back. I flush it when I can with Salt-Away and perform general maintenance and that's it. Don't worry about a few days or even a few weeks. Outboards are built for this environment and they're more corrosion resistant today that ever before. Flush when you can and enjoy. Chris
Tohsgib	posted 09-16-2010 10:32 PM ET (US) Yeah, worry about it in 10-15 years. Go back north and flush if not convenient. What I do when I go to the Keys is I stop on Alligator alley and back it in to the fresh water and let it run on the trailer for a beer. DONE!
Destin_Dauntless	posted 09-16-2010 11:35 PM ET (US) Man, saltwater kills everything. I use salt-away and flush after every use. If I don't get it that day, I make sure to get to it the next. My house is 10 years old, the same as my whaler, and the metal entry lights over my door are falling apart from salt in the air. Oh, and my tilt motor rusted on the back side against my transom where you couldn't see it on my 200 opti. That was a pain to fix.
PeteB88	posted 09-16-2010 11:36 PM ET (US) I don't know why fresh water jockeys seem to worry so much about saltwater and their engines. "It's NEVER been in salt water." is what we hear all the time up here in the Land of Unsalted Seas. .Actually Unsalted is becoming a brand that I think started with Great Lakes surfers. As regards outboards and our boats they are indeed intended for salt water use. There must be 10s of thousands of them in service. Certainly corrosive environment is worrisome but so what? I know cats on both coasts that don't flush their boat motors.
elaelap	posted 09-16-2010 11:52 PM ET (US) I flush after every saltwater use, and wash down my boat and motors with fresh water as well. Doesn't take very long and can't hurt, so why not? But that's not really the topic question, is it? I don't know the answer, and I'm not sure anyone really does. Probably many other factors are involved: salinity of water, temperature and humidity, frequency of use, etc, etc. Tony
tedious	posted 09-17-2010 08:30 AM ET (US) Exactly the same experience as Chris - our Maine boat goes in the saltwater in May, lives on a mooring and gets used all summer, and comes out in early October. The only flushing it ever gets is while we're fogging it for the winter. Don't stress over a few days - sheesh. Tim
jimh	posted 09-17-2010 08:36 AM ET (US) [This discussion of outboard maintenance has been moved to REPAIRS/MODS.]
jimh	posted 09-17-2010 08:44 AM ET (US) The effect of saltwater on an engine is likely influenced by the temperature of the water. I notice that comments from boaters in Maine, with cold saltwater, reveal a more casual attitude about flushing than you often see from boaters in areas with saltwater with tropical temperatures. The combination of sun, heat, and saltwater in areas like south Florida probably create conditions of greater concern than you would find in Maine or in the northern Pacific coast.
hauptjm	posted 09-17-2010 09:58 AM ET (US) Where I keep my boat on the MS Gulf Coast, I have to travel about 15 minutes up a river and then 5 minutes through a bayou to get to my dock. All of this is beautiful, bronze fresh water. By the time I arrive at my dock, I'm fully flushed with fresh water. When I travel to other locales, I try to flush daily or every other day if I don't run the boat in fresh water.
weekendwarrior	posted 09-17-2010 12:14 PM ET (US) I am in S FL and in summer water temps are in the upper 80's (in the 90's in some areas) and air temps in the upper 90's with hot sun. Aside from the typical salt-induced corrosion (mostly bolts, just try to disassemble a block or lower unit after 10-15 years of salt use and no flushing or rinsing), the problem I have seen over the years is the salt water left in the motor dries up quickly (relatively) and leaves the salt behind. This salt is really hard and doesn't rinse out with just plain water, so over time it builds up and can eventually cause problems. If you use the motor often and it stays wet then it's not such a problem. But lots of people use it once every month or two. I am religious about flushing myself and after a couple years when I change my thermostat, it has hard salt chunks on it, so an unflushed motor here would surely be worse. Salt definitely builds up. If you use the boat daily the I wouldn't worry about flushing if it's a PITA, until you're ready to stop using it. Engine makers make a point of addressing flushing (my manual explicitly says flush after salt use) so I think it's important, but if it gets daily use then what's the point.
tedious	posted 09-17-2010 12:17 PM ET (US) Jim, one other thing to point out on the difference in flushing attitudes between casual Maine, and fussy Florida, is that a higher proportion of boats in Maine tend to be on moorings rather than in slips or at docks. The greater tidal range has a lot to do with that - it's quite expensive to build a setup that can support a boat properly through a 10 foot tidal range. I would flush my motor more often if I had 1/4 mile of hose:-). Tim
tom976	posted 09-17-2010 04:39 PM ET (US) The previous owner of my boat had it moored. Maybe flushed it once a year. When I got it and had to pull one of the heads, I opened up the water jacket to see whats up while it was all apart. WOW lots of salt in there. Thermostats were shot, internal anodes on my yamaha salt water series II had to be replaced. (motors a 1997, I got the boat in early 2009) This was a motor designed for the saltwater and still had some minor issues with salt water. These days every time I come back to the dock I hook it up to water before I wash her down. Tom
tedious	posted 09-18-2010 09:33 AM ET (US) I am not sure I'd consider having to replace the thermostats after 12 years all that unusual, regardless of how much flushing was done. And the cylinder head anodes should be checked every year as part of routine maintenance - we check ours every year, and usually replace them every third year. Tim
contender	posted 09-18-2010 10:16 AM ET (US) You have to flush your engine after using it in salt water(if you want it to last) other wise the inside water jackets, thermostats and senders will malfunction. Once the water drains out of your engine (back home on the trailer) the salt remains, and not only does the salt remains but it starts to expand and clog the arteries of the engine. Salt is also a corrosive and the salt water running through an engine is like sand paper on the metal on the water jackets and other components inside. Its your choice.
Tohsgib	posted 09-23-2010 12:07 PM ET (US) I have [three older outboards] in my shed that are all saltwater engines and antiques. Maintenence is the key, not what the level of salinity.
Matt F	posted 09-23-2010 01:49 PM ET (US) Here in Mass, I can't think of anyone who flushes after every use. Boats go in in the late spring, come out around now and are flushed prior to being put to bed for the winter. Come to think of it, I don't think I could flush it if I wanted. Spending fifteen minutes running the hose a the dock only to have to motor back out through the very same salt water to the mooring seems problematic....
jimh	posted 09-24-2010 09:36 AM ET (US) As a freshwater boater, I can acknowledge we perhaps hold the corrosive effects of saltwater in too much regard. Following the rare times I have used my boat in saltwater, I try to thoroughly flush the engine, the boat, and (most importantly) the trailer with freshwater. If I were an habitué of saltwater boating, I probably would not go overboard with flushing the internal cooling passages of the engine after every use.
edgarop	posted 10-03-2010 08:11 PM ET (US) I run my 1973 evinrude 115 out of the Sf bay area mostly Bodega bay and always flush it when i get home. i run it on the hose bib for 10 minutes. ive owned it for 5 years and never had a problem overheating. the only thing that ive dealt with is siezed water impeller bolts. broke them in the lower unit had to drill out and put some HELI coils in there.
Chuck Tribolet	posted 10-04-2010 01:26 AM ET (US) Salt (sodium chloride, NaCl) is highly soluble in water. If there's something white in there that's not flushing out, it ain't NaCl. Chuck (I flush my Evinrude 90 after every saltwater use. It's nicely set up, in that I don't have to run it to flush it. There are female hose threads at the back of the block, run water, done. I takes about 1 minute of my time, about five minutes elapsed, during which I'm either stowing stuff I took with me or enjoying a brewski, or bot. I've got 1000 hours over 13 years, probably 800 days underway on saltwater.)
weekendwarrior	posted 10-04-2010 07:38 AM ET (US) Whatever it is, there's bunches of white chalky and chunky stuff in the passages and on the thermostat. I will try to remember to take some pictures next time I swap the thermostat. I have tried to take a few old salt water engines apart, engines that were flushed, and always ended up with several bolts that were corroded, some of which just broke off before you even get any real torque on them.