flushing whith WD40

[Tom]

I purchased an old Honda 4- stroke 7.5 hp outboard. The motor has a two prong female plug for a cable to charge the battery. Anyone know if this should be wired straight to the battery?

Also, when I saw the new WD40 cans with the attached red straw it gave me an idea. There is about one foot of small rubber hose that takes the raw cooling water from the port side of the engine around to the back and then out the bottom of the engine cover. At the end of the day, I lift the engine out of the water,  I take the hose out of the back of the cover, leave it attached to the engine,  hold it straight up, stick the new tip of the WD40 can in the hose,  squeeze it with my fingers and blow WD40 back down through the engine cooling system. I have put a pail over the bottom of the engine and a tablespoon of water comes out and a small amount of WD40.  Do you think this is an effective way to flush a small ob?

[Restharrow]

I had a Suzuki 6hp - 4 stroke that I connected direct to the battery.  No issues over several years.

Steve
CP 23 (SOLD)
CP 25 (SOON!!!)

[TedStrat]

I purchased an old Honda 4- stroke 7.5 hp outboard. The motor has a two prong female plug for a cable to charge the battery. Anyone know if this should be wired straight to the battery?

Also, when I saw the new WD40 cans with the attached red straw it gave me an idea. There is about one foot of small rubber hose that takes the raw cooling water from the port side of the engine around to the back and then out the bottom of the engine cover. At the end of the day, I lift the engine out of the water,  I take the hose out of the back of the cover, leave it attached to the engine,  hold it straight up, stick the new tip of the WD40 can in the hose,  squeeze it with my fingers and blow WD40 back down through the engine cooling system. I have put a pail over the bottom of the engine and a tablespoon of water comes out and a small amount of WD40.  Do you think this is an effective way to flush a small ob?

My 2 cents for what it's worth; wd40 is petroleum based and could rot out the rubber hose over time and maybe even the rubber fins on the impeller if i can picture what port you are referring to. I would probably just stick with  fresh water.

[skip1930]

Forget the WD-40. Are you in salt water? Are you in frozen water?
Why are you flushing? The impeller allows the water to be elevated to cool the engine by flooding the water jacket.
Are you full of mud? Even then I would not fool with it. Next time the engine is started, it'll flush out what's in the cooling system.

This does it by it's self. You don't need to help it. Keep the inlet screen clean and that's it.
When she's running, check to see if she's peeing.

skip.

[Tom]

Thank you all for your comments. Skip,  I sail in salt water and there are no issues with the cooling system,  no clogs or mud, the engine works fine.  And I'm sure most of the salt water drains from the engine when it is shut off and lifted up, but sometimes the engine is unused for weeks,  so to get the last little bit of salt water out and to "coat" the interior I thought squirting WD40 back down the "pee hole" sounded good.  By squeezing the rubber hose around the new nozzle on the WD40  I can pressurize the system. 

Steve,  Thanks that's what I'll do.

Ted,  I wonder if letting fresh water just drain down would work as well?

[Bob23]

Tom:
   I'm not sure I'd do anything. My Nissan 8hp 2 stroke sits unused for a few weeks at a time and I also sail in salt water. I normally like to sail off and back on to my mooring so just to keep the motor from feeling lonely, periodically I'll go out and motor around for a half hour just to keep things moving.
   At the end of the season, the motor goes into a barrel of fresh water where she gets her fall washout. If you're in a marina, maybe you could get one of those earmuff thingys and do a fresh water flush but I'd forget the WD-40 idea. But you do get an "A" for thinking about your motor.
   I've heard that a vinegar solution flushing at seasons end may remove corrosion and crud from the cooling system of a motor but I haven't tried it yet.
Bob23

[TedStrat]

Definitely use the fresh water Tom if you can - if it's on trailer use the muffs or garbage can. If on a mooring maybe you can get a sports water bottle with a nipple on It and squirt in fresh H2o but don't use the wd40. If there are any mechanics on the forum reading maybe they can weigh in but I feel the wd will rot rubber eventually - more damage than the salt left until end of season. I have replaced impellers on my outboards and they are more fragile than you think and will deteriorate. Good luck - you will figure out best way to handle
-Ted

[HideAway]

I agree with the others - never use wd40 for that purpose.  We sail only in salt water.  It is very important to flush the engine with fresh water after every use.  I used to tip our 8hp evinrude up after returning to our slip.  Later I found that doing so trapped sea water in some of the smaller channels inside the hot engine.  I spent hours rebuilding the thermostat,impeller, and the cooling inspection plate -- some channels were completely blocked. I was to the point of pulling the head when I discovered salt off.  After many flushings with west marine s salt off we have a cool engine.   And I do not tip the engine up unless sailing.

I have used wd40 in a pinch to start the engine - squirted directly into the carb - however carb cleaner does a better job. 

[CaptRon28]

Most outboards have a flush port where you can attach a garden hose. I do that just about every time I take the trimaran out. But you probably can't do this if you're on a mooring. Also - there are products on the market with names like "Salt Away". West Marine has their own version as well. They do a pretty good job of getting rid of the salt residue left over, and they coat the cooling system with a Teflon like chemical for future protection. I usually do this at least once a year, including the seawater cooled inboard diesel on the Horizon. The Yanmar single cylinder diesel does not have a heat exchanger and you wind up with damaging salt residue inside the block.

[Tom]

So it would seem that my WD40 idea is "dead in the water".  Glad I didn't run out and buy a case of the stuff!  My boat stays in the water all season and I have no access to a hose so I do like Teds suggestion of rigging a sport drink bottle so I can squeeze the fresh water and Salt Away down through the engine.

I purchased my CP 23 (EMILY) over a year ago and except for one shake down sail last Nov.  I have done nothing but work on her.  She was in bad shape. I can't tell you how much help you all have been to me.  Thank You.