Salt residue, Why ?

[bustaonenut]

I always notice some salt residue on the leg of my outboard the day after i use it. The salt builds up where the leg joins to the bottom half of the shaft (just above the cav plate) the gasket from where the propeller joins to the gear case, and inside the propeller itself.

I trim the motor down when flushing and use muffs, i've tried anywhere from 3-5 minutes and sometimes even flush the motor, wash the boat then flush the motor again.

The boat is then put in the garage with the motor trimed right down, then usually the next day when everything is dry you can see the salt crystals.

Its a six month old Mercury Lightning XR 40hp elpto.

[Blackened]

G'day

Chances are it's baked on with the heat during the days use

Dave

[bustaonenut]

the salt only comes once the boat has been put away and dries, it looks like it seeps out of the motor

[Blackened]

G'day

Double check it, usually it's hard to spot as the motor is usually always wet when at sea, and is hard to spot it

Dave

[sempre]

Septone rust and stain remover gets it off .
Sam..

[seawasp6666]

it happen leg gets hot pool acid works a treat

[bustaonenut]

thanks for the responses guys but its not a baked on salt. There is definatly no salt when i put it in the garage and even if i check a couple of hours later when everything is dry there is still no salt. It takes to the next day to show and you can rub it of easily with your finger. Its as if for some reason salty water drains out of these gaskets even after being flushed well.

Its just a pain because i have to take the boat out again and flush it, and when i do its fine the next day.

[bigjimg]

All the salt looks gone to the naked eye but in fact traces remain that draw moisture from the air which results in the salt crystals reforming.As long as you get to them the following day there is no harm done.Wipe over the affected area after rinsing with a rag moistened with light machine oil.Jim

[oldboot]

I'm speculating here but.

consider you flush the motor for a while then......when you disconnect water left in the cooling circuit has to dribble out....it may take some time for all the water to drain out of all the parts of the cooling circuit.

NOW
If the thermostat does not open there will be a dead end portion of the cooling circuit behind the thermostat....water will flow thru the bypass circuit but not thru the thermostat......thus there will be a little salty water left behind.

I flush my motor in a 44 gal drum and it takes quite some time 10 to 15 min for the water at the outlet to come out warm... indicating that the thermostat has opened.

before you finish flushing is the water comming out of the outlet at the bottom of the leg warm.....my telltale never runs warm.

cheers

[BaitThrower]

Yeah sounds like thermostat not opening up fully while you are flushing. Flush the engine for a good ten minutes to ensure this happens and see if it makes a difference?

[jtpython]

Ok i know what you are on about my Mercury does the same............ doesn't do it for at least a good couple days and to me seens to come from up under the cowling somwwhere as it must all congretgate in little spots then run out in drips some how.
Now i have run the motor for ages used a hose up underneath after flushing and sprayed RP7 and of like to see if this sill stop it but it doesn't. But it is in spots some times as large as a 1 cent piece .Mine is a Mercury 140
And i spend a lot of time cleaning the motor down this is usauly on the Anti ventilation plate
JT

[Noelm]

pretty common thing, but the Merc being Black it is easier to spot, it is just salt water that has been caught up somewhere and slowly leaks out over time, or is just caught in the joins and takes a while to dry out, one thing for sure, DO NOT USE POOL ACID on it, pool acid is Hydrochloric/Muratic acid and it will eat Alloy in a jiffy!

[nickstock]

I also have the same problem on my 70 yammy. It sounds obvious, but I use 5 tablespoons of (hand) dishwahing liquid in a ten litre bucket of water after I have already washed it down. The dishwashing liquid seems to leave a ''gel'' coating on it and have not a problem since.

[oldboot]

be carefull with leaving detergent residue arround or flushinf your motor with deterdent too.

Detergent ( generaly) is mildly corrosive, is hydroscopic and breaks down surface tension and allows water to penetrate into places that it wouldn't otherwise.

I have no problem with using normal concentrations of detergent for a sudsy wash followed by a thorough rinse but concentrated detergent particularly when not removed I don't think is a good idea.

many of the dishwashing detergents will have some sort of additive to reduce water spots and streaks on crockery... But my understanding is that it hides the problem and not remove the salts that show as the problem.

If the salt residue is on the cav plate... In my view it is almost certain that it is comming out of the cooling system...... most motors there is a cooling water outlet just above the cav plate..... bear in mind also the exaust system and the cooing system and involved with each other.

in most motors it isn't a simple case that water goes in "here and out there".
On my motor I can point to at least 8 places that water comes out of the motor.

It can seem that you are running your motor for ever...... but has the thermostst opened..... with a cool supply of water it may not open at all.

If you are looking for a "chemical solution" SaltX might be worth a look.....I have heard much about it .. but havn't yet tried it.

No consider that the salt residue on the exterior of the motor may be a very small part of the whole situation.

cheers

[bustaonenut]

i might set up a a drum to flush the motor out next time that way i can put it in gear and give it some revs, trying to get it a bit warmer to see if that makes a differance.

The water coming out of the telltale at the moment is warm (you can leave your hand under it without it feeling hot)

[oldboot]

A drum is certainly a more civilised flushing experience.

depending on where your teltale comes out of the cooling system being warm may even indicate the thermostat is closed.....

The flow out of the leg is a better indication...... remember in normal operation the thermostat opens and closes and may not be completly open or completely closed at any given time.

It is all a bit different to the cloased circuit cooling systems we have in cars.

cheers

[Mindi]

pretty common thing, but the Merc being Black it is easier to spot, it is just salt water that has been caught up somewhere and slowly leaks out over time, or is just caught in the joins and takes a while to dry out, one thing for sure, DO NOT USE POOL ACID on it, pool acid is Hydrochloric/Muratic acid and it will eat Alloy in a jiffy!
Yeah Noel....my merc does the same and the black makes it really obvious. Agree on pool acid...absolutely not...did you even make hydrogen in soft drink bottles as a kid by putting some dilute hydrochloric onto zinc recovered from old torch batteries..? then dropped a match in the drink bottle..?

[Noelm]

yep, makes a neat bang huh!