Leaky Blue Knob

[SwellLife418]

I have a dripping leak coming from a blue knob located foward on my engines. I have twin Merc. 250s. I believe it is part of the cooling system. It only drips when running, and for a while at port. I am wondering what it is and how to fix it.

email me at nicholas.dennis418@gmail.com and I can email you a picture if you need it.

Thanks for the help!

Nick

 

[rcknecht]

with the engine shut off unscrew the knob and replace the "O" ring on the knob...

 

[Skuza]

This is more than likely your raw water cooling circuit drains. They sell the whole blue plug and I'm assuming it includes an O-ring.

 

[Maritime Matt]

Yup, thats what they are. Raw water drains on block and manifolds. They come with the o-ring. Good to keep a spare.
Matt.

 

[saltydogz]

Try the new plug or O-ring first, but I had the same problem last year tried a new blue plug still leaked...took the unit off to see what was going on and the female thread of the Water Distribution Housing were that blue plug goes in had a small crack on the bottom do to over tightening or water was in between the threads and cracked it when it froze... so you will need to replace the housing unit ($150).