Thermo Switch removal

[SlayerT123]

Hi All,

Before I attempt to remove the 2 thermo switches from my 2 stroke 40HP 1997, I just wanted to know if they are removed by unscrewing the black rubber (which has 2 wires), or do they just pull out?

Thanks,
Tom

[99yam40]

there is nothing to get a hold of to turn, should just slide in and out.
used a white heatsink compound when I reinstalled the ones on my C40TLRX

I am trying to remember if the head cover has to be removed or something else that holds them in.
will need to look closely to make sure.

why are you trying to remove them?

[boscoe99]

They are a press fit. Grab as much of the thermoswitch body as you can and wiggle them out.

[SlayerT123]

I went to install a temp sender and once I removed the 14mm plug from the head, I noticed the water passage behind it was completely blocked with salt and corrosion. I cleaned the hole out and attempted to flush it however no water got through into that area. I figured I’d take the whole head off and clean the passage ways along with cleaning the water ports in the exhaust side.

I wanted to take the switches out so I could dunk the cylinder heads on solution overnight to make the job easier.

Any recommendations?

[TownsendsFJR1300]

Rydlem is often used. Citrus, as shown below seemed to work VERY well...

Last two heads I did was off a 200 2 stroke. Most was done manually with small tools, small SS brushes, etc. You'll find the salt pretty hard and embedded...

Citrus cleaning:
http://www.yamahaoutboardparts.com/f...h27868-p2.html (Post #21)

Also
http://www.yamahaoutboardparts.com/f...g-th19434.html

http://www.yamahaoutboardparts.com/f...m-th23666.html



.

[SlayerT123]

Thanks for the recommendations I’ll look into them. Not sure I they have the same products here in Sydney, hopefully I can find something similar.

[99yam40]

Citrus acid powder should be available any where.
ridlyme marine descaler should be available also anywhere there are marine environments, maybe or maybe not

[rodbolt17]

bug juice.
also called cool aide or lemonade powder.
cleans the snot out of brass fittings as well.
in the USN we made it in 5 gallon jugs.

[99yam40]

I guess the big question is how strong should you mix the citrus acid for cleaning things

[dray0151]

I guess the big question is how strong should you mix the citrus acid for cleaning things

Thread 33 is the mixture I believe.

http://www.yamahaoutboardparts.com/f...h27868-p3.html

[rodbolt17]

we simply mixed it per the instructions on the packet,we actually drank the stuff while the brass was soaking.

[99yam40]

says 10 or 13 Oz of powder per gallon of water

I wonder if all powder is the same concentration/strength

[SlayerT123]

Just for FYI, managed to descale and clean all water galleries to Cylinder head and exhaust. I've attached a link to a video I took of the Citric Acid bath. You'll be able to see the tiny bubbles showing the stuff dissolve the remaining corrosion. I'm amazed at how well it worked, thanks for the tip. As you can see from the before pic, the left side of the exhaust cover was full to the gasket level of salt and crud. I scrapped a large amount out, and then let it soak in the citric acid for about 1 hour or so.

In the end the tray was full of crap that had dislodged. I would definitely recommend using this method.

Here is the link to the vid clip: https://drive.google.com/open?id=1dW...11PBGEuJhmy6Gk

[zenoahphobic]

I like to see things at work. Did you Heat the solution cause I can see steam?
Did you notice any aluminium dissolved or attacked by this acid?

[SlayerT123]

Yes I put the tray on the stove and let it simmer slightly like what the other links suggested. To be honest i didn’t notice any alloy dissolve apart from what the salt corrosion had already done. The corrosion was pretty bad especially where it was completely blocked up, as you can tell from the after pic, one of the bolt hole wall was corroded.