Outboard Motor Flushing

cbadmin · Joined: 23 Oct 2003 Posts: 206

From: Mike (Original Message) Sent: 11/17/2002 3:48 PM
I have some questions about the flushing port on my Honda 75 (the one that takes the screw in hose adapter). Is the flush provided through this port adequate to completely clean the cooling system? How long should the flush water be left running? The boat was last in mildy slaty water, and I am wondering if flushing through this port is all that is needed for winter storage.

Thanks,

Mike

From: LesLampman Sent: 11/21/2002 8:18 AM
Hi Mike,

I do not believe that there is a definitive answer to this questions and I've seen no hard data to support any particular argument.

My feeling is that the flushing port probably works best when the motor is still warm. It is my opinion that it was added primarily to allow fresh water flushing when the boat was still in the water and as such is a compromise. If the engine has cooled down then I suspect that running the motor with water fed to the lower unit would be the best thing.

BTW, the motor should not be run when using the flush port as the impeller in the water pump will be damaged; it's mostly running dry at that point.

I've also heard of tests that indicated that on larger motors that flushing had little effect of the three year period of the test. I'm conservative enough to feel better when I flush the engines.

FWIW,

Les

From: Mike Sent: 11/21/2002 4:45 PM
Thanks, Les. One more dumb question. What keeps the cooling water from running out of the flushing port when the engine is running? It looks like a straight shot to the cooling system. Is that the thermostat housing the port is plumbed to?

Looks like one more trip to the lake.

Mike

From: LesLampman Sent: 12/1/2002 6:35 PM
Hi Mike,

There is a check valve where the hose from the flushing port connects to the engine.

Les

From: Mike Sent: 12/1/2002 6:59 PM
Check valve? What'll they think of next?!? Thanks. I get bugged by the simplest of things!

From: Fishtales Sent: 2/18/2003 11:12 AM
Fishtales is used primarily in saltwater. I run white vinager through the flush out system. I was using "salt-away", but that cost to much. I use the flush kit supplied with "salt-away" but I put white vinager in it.
I also wash the exterier of the engine with white vinager- it takes all the baked on salt deposits off the engine. First I rinse the engines off and apply vinager with a sponge. Sometimes you need to let it soak in and use a little elbow grease, but when your done, it is nice and clean.
Spraying the trailer down with the vinager helps to keep the salt cleaned off, too.
I keep vinager in the flush kit bowl and use that to rinse the boat and trailer off.
Roger

From: 2nd Byte Sent: 2/18/2003 11:57 AM
I/ve gone the same route, switching from Salt-Away to the white vinegar. You need a printing press to be able to use the Salt-Away.

From: josepepper Sent: 6/4/2003 2:09 PM
How about setting the motor in a 10 gallon bucket with a hose feeding fresh water and just letting the engine idle for a few minutes?

Reel Fun · Posted: Fri Sep 17, 2004 10:13 pm Post subject: Flushing Bags for Outboards

Just curious...Has anyone used these flushing bags?

http://www.burgees.com/FlushingBag/MoreAbout%20FlushingBags.htm

I just purchased a 1987 16' Angler in Spokane... it's never seen saltwater... and want to treat it nice...

Sounds like maybe one of these Flushing Bags used with a little White Vinegar might do the trick?

Best Regards,
Matt

Mr. Fisherman · Posted: Sat Sep 18, 2004 6:01 am Post subject: Yep!

Matt, I have that very one and I can't say enough good about it.
Highly recommend it, you will love it.
I wouldn't be without mine and wondered why it took so long for me to get one...

Mr. Fisherman · Posted: Sat Sep 18, 2004 6:06 am Post subject: White vinegar

don't know if it is true or not but I have been told that vinegar is very bad for some seals and gaskets. I don't use it. Just lots of fresh water.

Reel Fun · Posted: Sat Sep 18, 2004 10:42 am Post subject:

Thanks for the info... I'll go ahead and get one and give it a whirl.

Best Regards,
Matt

Chuck S · Posted: Sat Sep 18, 2004 12:57 pm Post subject:

I have no experience with outboards in salt water, but do with auxillary engines on sailboats.

Salt is not only corrosive, it will precipitate out of the water in solid form and clog the cooling passages in your engine. Inboard engines used in salt water ideally use a heat exchanger (a radiator which keeps cooling and seawater separate) or must use a low temperature thermostat to keep the salt from coming out of solution. 140°-150° thermostat works well.

A low temperature thermostat never allows the engine to get up to good operating temperature so things like spark plugs need to be checked and replaced with different heat ratings sometimes.

I don't know if a low temperature thermostat is available for your salt water outboards, but it bears investigation. If there isn't you'll need to "desalt" the system frequently. Mere fresh water may not do it, we had to have our cylinder heads "boiled out" every couple of seasons despite a low temperature thermostat and mostly brackish water (Neuse River) rather than salt water.

There are desalting systems commercially available.

-- Chuck

Reel Fun · Posted: Sat Sep 18, 2004 10:55 pm Post subject:

Thanks for the info... I can't see myself spending alot of time in the saltwater, so I'll try to flush the motors real good and maybe use a
salt-away type of product on the rare occasion I'll launch in Puget Sound.
Headed back to Vancouver, WA in the Morning.. going to try and get out on the Columbia River for an afternoon/evening fishing adventure.

Best Regards,
Matt