ZR409 Fresh Water cylinder block plug location

[ericchile]

Newbie question.

Does anyone know where the cylinder block plug to drain the fresh water (antifreeze) on a ZR409 CED full closed system? It's the only plug I couldn't locate...

It is probably the same plug on all 409 s...

Thanks!

[ericchile]

Couldn't find any diagrams in the manual that indicate where the block drain plugs are for the 409/450...



This was the closest I saw and it didn't show the block....

[ericchile]

I feel like I am talking to myself.

On the 330 I believe the knock sensor is where you drain it out of the block. I wonder if it s the same for the 409?

#7

[ericchile]

Bump... anyone know for sure? Don't want to pull the knock sensors if I don't need to.

[scottb7]

I don't know...but you are so lonely on this thread. If it was me I would just pull the knock sensor. I have the 343 and that is what I do. It is so not a big deal. Just carefully take the connector off and go for it.

[dDavid]

II'm looking for the plug locations also. I have 3 plugs from where my son winterized the boat last year and can't find where they go. I've downloaded the manual and it doesn't show where the plugs actually go. Any help would be appreciated.

[dDavid]

Oh, the boat is 2014 G21 with ZR409 CES. Might be 2015 I'm not for sure.

[Infinity]

David...look at the above diagram, 2nd post. I tells/shows you where they all go and most of them are pretty obvious. The one you cannot see easily is the one that goes in v-drive (one of the ones that you use socket to remove). I use a wet vac to pull as much water as I can when I drain water to winterize and then re-install the plugs immediately. Course I also fill system with RV anti-freeze cause it helps against corrosion and is another method of insurance against freezing. Keeps you from forgetting where parts go too.

Eric...guessing you are looking for that plug to change the existing anti-freeze? I have not done that on my boat with same engine since a 2014 and not needed yet, but am guessing you are correct that knock sensor is the drain for anti-freeze on the closed cooling. My manual shows same diagram you have.

[scottb7]

Maybe you found it by now...but yep, above is right, look at #4 on the diagram that is where two of the brass looking ones go, and I also re-install after draining....

[dDavid]

Thanks guys! That did the trick.