Freshwater flushing outboards while cruising, practicallity?

[Franziska]

Originally Posted by thomm225

There is one guy though at my marina that sails a small 25' sailboat with a newish 9.9 Mercury on a bracket.



He flushes his outboard with fresh water for maybe 5 minutes after every sail.



He sails single handed.



It seems to take him about the same amount of time to get his boat backed into his slip to complete this task, but he does it each time without fail

Well if you are docking it surely is a good thing to do. If you are primarily at anchor its rather complicated as you normally do not have an abundant source of freshwater.

[SV Magnolia]

We have both a Yamaha 20hp and a Merc 6.6hp.
These have both been with us for several years now.
The Merc has never been flushed, not even once.
The Yamaha we flushed exactly once. This was when we needed to store it well above sea level in a locker for some weeks.
As it was explained to me by our local outboard shop mechanic, when I went in to buy a flush kit;
" Why do you want to flush it? The problem with flushing is that it's really hard to get the correct amount of water pressure in there and that usually caused problems with damaging the impeller and you would never know until more damage was done." He went on to say, "Most of the service I do here is from impeller damage probably done by flushing." He did go on to tell me that, " The only time you really need to flush is if you are storing an outboard above sea level." I asked him for clarification on that, like, " What if I store it up on the stern rail, It's like 8 ft above water" And he basically told me, knowing our lifestyle (as full time liveaboards who also will be doing a lot of cruising) that I would probably never need to worry about flushing and he just reiterated that I wouldn't want to flush unless the outboards where stored well above sea level. The conversation ended with him explaining that what he means is that if I have a boat that I trailer out and store in my garage in town like up on a hill or something, I just wouldn't need to worry about it. So I left without buying a flush kit. I trust this guy highly. His family has owned and run an outboard shop for decades. Still not flushing and still zero problems. Both outboards run just like they did when they where brand new.

[R Hutcheson]

We have a flush kit installed on ours, so when we are at a marina, I will connect a hose and flush it out seems to work fine. The engine is 12 years old and we have been using it for three.

[Benz]

I almost never have a chance to flush by 8hp Yamaha, and occasionally when the flow has been clogged, I shove a piece of seizing wire up the hole and clear it. Mine has a flush fitting that bypasses the impeller, or at least doesn't endanger it, so I flush with confidence on the rare occasions I get to.

[PaulvR]

flush schmush,
but crucially,
always lift the motor when not on a dingy dock and always run the carb dry if you're not using it regularly.
I confess I'm a Yamaha guy (several 2 strokes over decades, 2-15hp), never flushed one in regular use, unless it was going into storage or run ashore or, oops, fell in the water!

[OneBoatman]

Buy a set of muffs and flush it when you get a few extra minutes or when you can get to hose. Two or three times per year and it should last at least 20 yrs. Keep a zinc on it and change the lower end gear oil at least every two seasons. My dinghy outboard is about 13 years old and it usually only gets flushed when I take the mothership to be hauled upriver at the end of the season.

[SoonerSailor]

My understanding is that flushing is most strongly indicated when using ethanol containing gasoline. Something about the interaction of exhaust, sea water and ethanol promoting the buildup of crud in the exhaust system.

[thinwater]

Originally Posted by SoonerSailor

My understanding is that flushing is most strongly indicated when using ethanol containing gasoline. Something about the interaction of exhaust, sea water and ethanol promoting the buildup of crud in the exhaust system.

Post a link--we might learn something. I've seen nothing to that effect. Since ethanol burns very cleanly, this sounds like a frustrated mechanic or owner grasping at straws or rumors.

[Buzzman]

If the water supply is limited, then you need be able to flush with a small amount of water, not free flowing water.

Muffs, especially if they are custom fitted to your specific engine *might* be OK, (becasue I've never seen 'standard' muffs that did not leak profusely) but the feed to the muffs would need to be from, say, a deckwash pump picking up from a bucket of fresh water (perhaps half full, so around 4-5L) with the return line from the telltale going back into the same bucket.

This probably requires getting a machinist to tap a thread into the telltale hole, so you can screw in a fitting attached to a hose to return the telltale outflow to the water bucket.

This might be tricky for 'main engines' that are on drop down mounts or whatever, but feasible for the smaller, more readily detachable dinghy donk.

I recently watched "Wildlings Sailing" YT channel flush their small ancient 2-stroke dinghy donk with fresh water, just by sticking a bucket full of water over the prop and leg (i.e. they dropped the motor into the bucket then fixed it to the rail so it wouldn't move).

They added some 'flushing solution' that was a purpose designed anti-scale solution to assist with the cleaning, and the water definitely went darker and murkier during the 5 minutes they ran it. IIRC their telltale just dropped into the bucket...

But the motor then ran cleanly and pumped water again, which it had not been doing before the flushing operation, so they proved they didn't need a new impellor.

So a little bit of faffing around to save a quid or two.

But...it *can* be done if you want to badly enough, and does seem to be efficacious, at least, it was in their case.

[valhalla360]

Originally Posted by Chotu

Thomm:. She's asking about cruising, which means you don't have ready access to fresh water. Just whatever you are carrying in your tamks or making from a watermaker. Not living on land and keeping her boat at a marina.

Cruising presents different constraints, of course.

Cruising also varies greatly.

If you are living at anchor for months on end, the dingy is likely your daily driver, so there is a regular circulation of water that will limit build up.

If you mix in the occasional marina stop, putting a set of muffs on for a few minutes is very much viable.

That's what we do. Every week or two it gets a fresh water flush.