OMC Exhaust Plug

[lrlima]

1993 4.3 OMC<br /><br />The plug that needs to be pulled to drain the exhaust manifolds is driving me crazy. It is a brass plug that would acdept a square bit - like a socket wrench, without a socket attached to it. The problem is, a 3/8 socket head is too big and a 1/4 is too small...I've been to five tool stores and cant find anything that would get that plug out. Plus, there is only a couple inches of clearance to get to it anyways...<br /><br />I have pulled the two plugs from the block, and have taken the hoses off from the front of the manifold, but I still need to get those crazy plugs off.

 

[rodbolt]

Re: OMC Exhaust Plug

if you will drain the block then restart it with a bilge pump in a bucket of properly mixed non toxic AF you wont have to worry about them.<br /> sounds like the 1/2 sqaure drive 3/8ths pipe plugs. about half I see removed tend to bring the threads out with them.<br /> zip on down to a good hardware store and buy a section of 1/2 key stock and bend it.<br /> or rig up an AF delivery system like DonS posted and drain the block first and run it full of AF.

 

[DangerDan]

Re: OMC Exhaust Plug

I usually just drain the engine through the petcocks on the side then fill with AF. Try a allen wrench set for the plug.

 

[boatgrunt]

Re: OMC Exhaust Plug

I have a 89 OMC 4.3 and had the same problem. I used a set of vice grips to get the plug out. It will probably strip the nut, but if you can't get a socket on there anyway, who cares. When you put the old or new plug back in, smear the thread with grease to save yourself some trouble next year. I am not a techi, but in my opinion you should drain the exhaust manifold even if you're going to run the AF through it. The manifold plug area fills with rust and other crap. When you drain the manifold, this "stuff" should be cleaned out.

 

[Boatin Bob]

Re: OMC Exhaust Plug

Doesn't the manifold ahve a rubber cap on the rear end held on with a hose clamp? It should match the front end where the hose attaches, all you do is remove the rubber cap and the manifold drains, don't know why you are fooling around with that plug.

 

[Bondo]

Re: OMC Exhaust Plug

The problem is, a 3/8 socket head is too big and a 1/4 is too small...

That would be 5/16ths"........<br /><br />Like rodbolt says,....<br />Go to a Hardware Store,+ find a piece of 5/16ths" Square Stock,+ Use a piece of That........<br /><br />Then Replace it with a more Wrench Friendly Plug............

 

[lrlima]

Re: OMC Exhaust Plug

Thanks for the replies. I'll try a real hardware store today...HD, Lowe's, Advance didnt have anything. Will definitely replace with a better plug once I get it out.