How to locate drain plugs?

[Sea~Lah]

I tried posting in the winterization forum to no avail.
I would like to know where the drain plugs are for my 1990,7.4L mercruiser.
Any suggestions would be greatly appreciated!
Linda

 

[wish2fish]

posting things twice always goes over well here!:thumbsup:

 

[McNally260DA]

We have a 2000 7.4 MPI and I think I have 5 but I still check my manuals every year. You don't want to miss one. There locations are shown in the back pages of my small black owners manual. I also have a larger installation manual that shows there location as well. My motor is different I'm sure. Mine are blue plastic.

 

[my3sons]

Hello and welcome.
Giving specific info on winterizing is difficult because models can be different depending on drive options, year, type of cooling system, etc. We are (or least I am) reluctant to give info that, if not corect for your application, could cause freeze problems
Assuming you have raw water cooling, you need to get all the water out of your hoses, coolers, and block to winterize. The block drains on a 7.4 are located one each side of the motor, approximately in the vicinity of behind and next to the dip stick tube on one side, and the front of the starter on the other side if memory serves me right. They were brass hex headed pipe plugs on my motors. But there are also plugs in the bottom of the exhaust manifolds, and oil coolers. there are hoses that need to be removed so that the water can be allowed to drain out, and then finally fill the block with A/F.
Your post the other day asked for any ideas where you could get the info on doing this, and I am not sure, you might try asking someone with the same set up if you could copy their manual, e-mail mercruiser, or check out one of the Seloc or clymer manuals. Maybe hire someone to do it the first time for you and watch what goes on. It's not difficult to do, but if you miss something, the price you pay to have it done is nothing compared to a new block.
Good luck

 

[Jimmy Buoy]

I you have a Bravo Drive, you will also have a belt driven water pump. The pump should have a drain plug, but I used to crank the engine a couple of turns (not enough to start the engine) AFTER filling the engine and cooling water supply hose with antifreeze to ensure that seawater was out of the pump and a/f was drawn in to the pump. I filled the engine by removing the thermostat and just pour.

Also, don't forget to take a thin wire and ensure that the other plug holes are free from blockages which could prevent proper seawater drainage.

I did this with my last boat for 5yrs without issues. Good luck!