Engine flushing

[duggie12]

Folks apologies if this has been covered a million times

I read that flushing an outboard in fresh water after salt water use is very important and that terrible things will happen if you don't do it
But what about the engines that are in constant use in salt water or when it's not practical to do it. Do these engines just not last?

I was just curious

Thanks

[Fenlander]

My personal opinion...

Leisure users who go out now and again then flush/wash down after every trip often enable outboards to remain in outstanding mechanical/cosmetic condition at 20yrs old and more.

Similar infrequent leisure users who leave boats afloat with OBs in the water never flushed often end up with far more rapid aging.

Commercial users who leave OBs on but use daily do at least keep the flow of water through the passageways avoiding the drying out and blocking by salt deposits.

I guess the two images below show the difference between an OB left in and one cosseted...

[Iron Dials]

For people like myself who leave the boat on a mooring for the season flushing is not possible. This hasn't caused any problems.

(I do run the engine regularly and leave the leg in the water as long as I can after I turn it off so that the metal is as cool as possible when it dries out, thus minimising salt deposits from evaporation- my wacky theory)

[beerbelly]

my warrior had a Suzuki outboard so I could flush that through a screw in attachment whilst still on the mooring in the water luckily there was a tap nearby

[Striker]

You could take a container of fresh water to use for flushing if it really worries you. My RIB has a fresh water shower by the stern boarding ladder, so I have made an adapter so that I can use this for flushing (through the Suzuki flushing point) if I’m leaving afloat for any length of time.

[JonnyR]

So I think the general view is that flushing the engine is a good thing and its a good question to ask. So following on from this, my question is how much difference does it make if you can only connect to the engine's hose adapter to flush with the leg out of the water (when on a marina berth for example) compared to taking the boat out and putting on the muffs and flushing through when the engine is running? Obviously the latter should be better as the freshwater is being flushed through the entire system - but I'm just unsure how much of a difference it can make. Any ideas?

[Xk59D]

Had outboards I didn't flush from one season to the next as they were on a moorings, very little problems.

Ironically the worst engine I've had for cooling blockage is my current df200 that is flushed after every use. I've just ordered new cooling hoses as the block is clean internally as I'm sick of having to stick wire into the tell tale. I think I maybe ingested a jelly fish 2 years ago while on a trip is my best guess so perhaps not salt related but the point is it is always flushed.

Will an engine last longer that is flushed AND washed all the time....in theory you give it a better chance but I wouldn't lose sleep over it of you need to keep it on a mooring.

Some engines are worse than others for corrosion problems but salt will take its toll on them all eventually.

Luckily today we have pretty good oils etc and my outboard gets a liberal spray of corrosion guard HD on the saddle and normal wipe over with normal corrosion guard internally, it literally looks brand new after 5 years.

The worst thing you can do is not use an outboard so get boating more often

[jeffstevens763@g]

you can buy flush bags if on a mooring,
i flush with water every trip and been doing saltaway once a year. but been using citric acid on some other stuff so changing to that. way cheaper than salt away which saltaway is anyway. citric acid is a bout £5/kg plenty to put in a tub and run the engine for a while.
before anyone says i did a trial on bog standard alloy for two weeks no stain or corrosion. it's safe too just wear safety goggles

[Striker]

Originally Posted by JonnyR

So I think the general view is that flushing the engine is a good thing and its a good question to ask. So following on from this, my question is how much difference does it make if you can only connect to the engine's hose adapter to flush with the leg out of the water (when on a marina berth for example) compared to taking the boat out and putting on the muffs and flushing through when the engine is running? Obviously the latter should be better as the freshwater is being flushed through the entire system - but I'm just unsure how much of a difference it can make. Any ideas?

Doesn’t make any difference with the Suzuki as some of the fresh water runs back through the pump drain anyway. Water needs to be able to drain back when the pumps not running otherwise it would stand in the pickup pipe and freeze. The only real difference is you don’t run the engine whilst flushing using this method.

[Davie]

Originally Posted by JonnyR

So I think the general view is that flushing the engine is a good thing and its a good question to ask. So following on from this, my question is how much difference does it make if you can only connect to the engine's hose adapter to flush with the leg out of the water (when on a marina berth for example) compared to taking the boat out and putting on the muffs and flushing through when the engine is running? Obviously the latter should be better as the freshwater is being flushed through the entire system - but I'm just unsure how much of a difference it can make. Any ideas?

Why not run it on muffs when still in the water?

[Striker]

Originally Posted by Davie

Why not run it on muffs when still in the water?

Can be a bit of an awkward reach if on a large outboard, but nowt wrong with it.

[Iron Dials]

I think it's worth remembering that these engines are designed and built to be used in sea water.

As OP says, it's desirable, but, in the last 3 years I have had no problems related to not being able to flush out, no noticeable degradation in my engine inside or out (cosmetically or anything remarkable found during services). Previous small 2 strokes (black and white memories) were all meticulously serviced, but never flushed during the season without problems.

There is a danger of getting carried away with preventative measures.

I would be interested to see posts from engine owners who have had problems directly related to not flushing engine after every use.

[jonp]

I think those who rarely use their outboards and leave them with saltwater through the powerhead and thermostat may be running the gauntlet a little but will eventually come unstuck. It amazes me the amount of people who hand out advice on not flushing outboards who don't have any mechanical training with outboards.

Just ask yourself why manufactures put flushing points on outboards and why they recomend flushing them. Also ask yourself if manufactures are making any money from recommending you flush with fresh water, infact they are likely to make more money from those who don't flush.

If you don't flush please make sure you let anyone who may potentially buy your secondhand outboard so they know they may be up for some costly rebuilds. Yes outboards are marinised but manufactures expect and recommend simple basic care from owners.

This may help with flushing advice Outboard Flushing The Right Way - BoatUS Magazine. Our local boat ramp has around 200 boats launch everyday, we have around 10 flushing stations for flushing outboards when the boats are brought out of the water, I don't know of anyone over here who doesn't do a simple cost free flush. Outboards can be flushed on moorings.

[jonp]

Plenty of videos out there showing the harm from not flushing.

https://m.youtube.com/watch?v=RGUWzn_tYwI

[spartacus]

My auxiliary Mariner 4hp rarely used to get used, until a couple of seasons ago I fired it up when I added it to my inflatable tender. The tell-tale was blocked, and even although I cleared it, it wouldn't pump water. Got it home and stripped it down, to find the impeller completely caked in salt. This was on an outboard that wasn't used in the sea, but the leg did get sea spray during a run.

Moral of the story, run the engine religiously whether you're using it or not. If it's been used as sea, then flush it at the next available opportunity. If that isn't possible, then just run it.

I bought a salt-away solution for an end of season treat!