Broken Drain Plug Mercruiser 7.4

[Hoosmatroos]

Yesterdag, when we pulled the boat out of the water to put it in storage, I asked the club members to put it on a pedestal and leave it outside for 30 minutes so I could drain my block first before put my boat inside. Removed the hoses from the manifolds (no drain plugs there), removed the big hoses on the thermostat housing, removed the drain plug on port side of the engine (water was only dripping, even when poking) and then, tried to remove the drain plug on SB side but the SOAB broke and left me with the thread inside the block. Luckly the plug is hollow so the block drained for 10-15 minuten and should be empty.

Try to remove the left over thread in the next couple of weeks. Will try this with a left handed bolt remover (don't know the actual English word for it ) It's a pita to reach that spot. Ordered all new plugs (22-806608A 1) because the one broken looks dried out.

If you have any comments, please do. Otherwise I'll make some pictures on the way and place it here to help others.

 

[Volphin]

Soak the area in a penetrating oil like PB Blaster for a few days. THEN attempt to remove it. Keep poking something in the port side drain. You may still have water in there.

 

[Hoosmatroos]

I will use some oil there. But keep in mind that these plugs are plastic. Shouldn't be very difficult to remove but you never know

On the port side of the engine it stopped dripping after quite a while. Ik poked a lot in that hole (sounds strange, I know) but no sand or other junk came out. Even on sb side not much junk came out.

 

[Volphin]

The plastic ones should be easier to get out. The oil will still help. Just don't use a torch! LOL

 

[tpenfield]

the Port side may still have water in it, unless it continues to 'drip' at a reasonable rate. The port and starboard sides of the engine block only 'swap' water at the circulating pump level, which would leave a 'non-draining' side about 2/3 full of water.

 

[Bondo]

removed the big hoses on the thermostat housing,

Ayuh,.... Ya gotta pull the big hose off the circulatin' water pump, rather than the t-stat housin',....

Water flows Downhill,...

I use a deck screw to prod the crud outa the drains myself,... you can get fairly aggressive at it,....

 

[alldodge]

Since you have the plastic plugs this should be a bit easier. The plastic plugs get screwed into an bushing (item 4). Remove the adapter and get the plastic out then reinstall or get another.
http://www.mercruiserparts.com/Show...05&bnbr=190&bdesc=CYLINDER+BLOCK+AND+CAMSHAFT

 

[Hoosmatroos]

Since you have the plastic plugs this should be a bit easier. The plastic plugs get screwed into an bushing (item 4). Remove the adapter and get the plastic out then reinstall or get another.
http://www.mercruiserparts.com/Show...05&bnbr=190&bdesc=CYLINDER+BLOCK+AND+CAMSHAFT

Oke, update time!

This adapter was already installed. Was hard to see. Tried to remove the broken plug with a left handed bolt remover but wasn't able to do that.

After a second look I could see the adapter and with a socket wrench I was able to remove the whole thing. Ordered a new adapter and will replace this next week.

On the port side I poked with a flexible piece and the rest of the water was pouring out.

Thnx for the help.

 

[Hoosmatroos]

Last update for this little issue. Last fridag I installed the new adapter like AllDodge showed. Put in some new blue drain plugs and used some grease on the threads. Allready changed my IAC and now only need to change the oil and filters.

Almost ready for the season to come in 6 weeks.

 

[Lou C]

If you can in the future use the metal drain plugs like OMC and Volvo used. They last forever and they
will not break like the plastic ones Merc uses. Just put some OMC gasket sealer on the threads and they will come right out even with salt water use.

 

[thumpar]

My Merc only uses the blue plugs on the manifolds. The others are brass.

 

[Hoosmatroos]

The blue plastic ones are cheap. I bought a couple of them. Will replace as soon as I see that they went bad.