Deposit Buildup in Outboard Question

[SeaHunt]

Firstly let me say I always flush my motor and for a good five or ten minutes after every trip.

Anyway I was half way to Mud Island last Saturday when my motor alarm sounded, there was a good flow from the tel tale but the alarm would sound as soon as I reved it for a while, I eventually idled back to the ramp without getting to fish.:(

After much thought I removed the thermostat and tested it in a sauspan on the stove and it doesn't open, which is a good thing as any other alternative could prove expensive.
On the back of the thermostat there was this green coloured crusty buildup of crap, and also in behind the thermostat on the walls of the opening.
Is this stuff salt or corrosion caused by salt water?
I would like to give it a good flush out with something before I put a new thermostat in.

Is there any additive I could safely flush through my motor to clear away this buildup.
Motor is 2003 60 HP Merc 4 St. about 300 hours on it.
Thanks.

[Jarrah Jack]

My mate up Darwin way fills his Honda up with white vinegar and leaves it overnight to dissolve all the crap. He reckons it works well. He got the idea off one of the yank marine engine discussion sites.

Would be interested to know if anyone else has tried it before I have a go at it though.

[Spaniard_King]

Sea Hunt,

Thats pretty standard and in no means detrimental to your outboard at this stage.

To reduce this build up simply flush your engine for a bit longer, ensuring the engine getts to full operating temperature.. the engine cylinder head should feel quite hot to touch (i.e should be able to keep your hand on it for 3-5 secs)

Also if the thermostat does not fix your issue with overheating you might find that there is a grommet at the top of the water tube which tends to grow closed and restrict the water flow to the powerhead. I have done 2 of these in the last 12 months (the local merc dealer did 12 last year) it requires the powerhead removal and replacement of the grommet.

[FNQCairns]

Pool acid works wonders...if your game. I tested the vinegar on some old corroded parts once, soaked them for over a week just for the experiment, also did bi-carb as well if memory serves, they where both failures (not complete failures but close enough) at removing the mineral salt complexes that causes gumming up.

[SeaHunt]

Sea Hunt,
Also if the thermostat does not fix your issue with overheating you might find that there is a grommet at the top of the water tube which tends to grow closed and restrict the water flow to the powerhead. I have done 2 of these in the last 12 months (the local merc dealer did 12 last year) it requires the powerhead removal and replacement of the grommet.

You know your stuff Spaniard_King.
That happened last year, but the tel tale was pissing like an old man with a prostate problem.
$850 went on that, which included a service, one of the reasons I decided to have a bit of a look at it myself this time.

[SeaHunt]

Pool acid works wonders...if your game. I tested the vinegar on some old corroded parts once, soaked them for over a week just for the experiment, also did bi-carb as well if memory serves, they where both failures (not complete failures but close enough) at removing the mineral salt complexes that causes gumming up.

I don't think I am game.:-?

While I would love it to be all shiney and new I dont want to risk stuffing any hoses or gaskets or coatings inside my donk..
Would Salt Away safely remove this type of buildup?

[darkside]

I always run some "pine o clean" or "domestos" through the motor when i flush it.

Put half a cup in a bucket if thats what you use to flush , or just add it to the "muffs" via a venturi system for the last minute or so.

The galleries always remain spotless and the "white salt " doesn't get a chance to build up because of the disinfectant.

"Cheap and effective"

I was shown this years ago by an "old salt" who swears by it, and I must admit it's worked a treat for me.!!