Water drain plug thread size

[Finn]

´Hello , do anybody know the thread size/type for the water drain plugs on a 2001 Mercruiser 7,4 MPI,I would like freshing up the treads before I put in new drain plugs.

[seapuppy]

finn..which drain plugs are you wondering about??..the blue plastic ones???

[Finn]

yes , the blue plastic plugs

[seapuppy]

ok...not sure what size they are ...but there shouldn't be a need to chase them out of the fittings....unless they have been damaged somehow...I'll check sometime today with maxum and see what they have to say.....
I think you just need to hold your tongue just right and pray to the boating gods....haha...just kidding...I'll get back to you on this....

[Finn]

some of them have leaked and there is rust in the threads so I need to do something

[seapuppy]

check the rubber oring...if they are missing..then get some new orings...they come in all kinds of sizes so going to a slightly thicker one might help......

[Finn]

okay , but I still need to do the threads, I can´t screw in the new plugs without spoiling the threads on the plastic plug :-)

[Finn]

The thread i 1/2 inch witworth , if somebody should need it :-)

[seapuppy]

oh man Finn... I forgot to go after that info for you!!...been really busy at work and all and just flat out forgot!!...sorry.... :shock:

thanks for posting the info on the web here....