Beta BZ 482 12.5HP - draining water jacket

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Beta BZ 482 12.5HP - draining water jacket

Postby Nick » Mon Oct 27, 2014 12:50 am

The coolant drain plug for the block on my Beta has a square nut on it that seems to be made of cheese, and I have been unable to shift it. It just threatens to become a round piece of cheese.

A friend has suggested drilling it out and replacing it, but I thought I would see if anyone had had a similar problem and solved it before I did that.
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Re: Beta BZ 482 12.5HP - draining water jacket

Postby Silkie » Mon Oct 27, 2014 3:18 am

Repeated cycles of heating and cooling and hammer blows has sometimes worked for me. Of course if the plug is a fairly substantial lump of metal and is on the underside of the block with limited clearance it might be difficult to manage either of these techniques.

A hole cut in a sandwich of a few layers of fire blanket and beer can might expose the drain plug and protect the block while you apply heat. One of those turbo gas lighters puts out a fair amount and is directable. Try not to set the boat alight.

If there is insufficient clearance to swing a hammer down onto the head of the plug, blows from the side might still be possible with a long-handled cold chisel. However you hit it make sure that the force is as nearly flat on whichever face of the plug as possible and that the blow is transmitted via an intermediary.

Is the square head sufficiently chunky and exposed that you could cut a slot in it to use a steel bar as a long lever?

Now that I think about it, it would be difficult to drill out the plug if it was on the underside of the block with limited clearance.

Anyway, my thoughts for whatever they're worth.
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Re: Beta BZ 482 12.5HP - draining water jacket

Postby DaveS » Mon Oct 27, 2014 2:08 pm

The water jacket should only occupy the top half of the block, so I'm guessing that the drain plug is on the side, about half way up. If so, then most of Silkie's suggestions, with which I agree, should be feasible. Is there room to get a large stilson wrench on to it? I have found this pretty effective as a "general persuader".

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Re: Beta BZ 482 12.5HP - draining water jacket

Postby aquaplane » Mon Oct 27, 2014 4:20 pm

I managed to sheer off one of them on my Volvo, without much effort I would like to add. I admit that I was working blind and may have missed the cock handle and gripped the body of the thing but it came off in me 'and yer 'onor.


The whole of the threaded section just sheared off and the remains looked to be extreemly thin.

I just looked at the Beta manuals and the drain cocks on there look to be a similar design if not the same MOC.

Am I right in remembering you have a Beta like Ash?
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Re: Beta BZ 482 12.5HP - draining water jacket

Postby Rowana » Mon Oct 27, 2014 4:45 pm

On Rowana I was able to get a open ended spanner, about 8mm from memory, on to the square, and out came the plug.
The plug screws into an elbow which is screwed to the block, I had a bit of bother getting the water to flow as the elbow was bunged up. Eventually cleared it with a bit of wire.

It's a bu99er to get to as it's under the fuel pump and very close to the engine mounting.

I would try the heat treatment already posted.

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Re: Beta BZ 482 12.5HP - draining water jacket

Postby sahona » Mon Oct 27, 2014 9:00 pm

My method would be - assuming access is available - grip the victim with molegrips tightly, bang, vibrate with a hammer while moving the molegrips BOTH ways (shoogle ) until some movement was observed then skoosh some penetrant and continue the bang/shoogle until free movement was observed.
The problem with threaded plugs is that there may be a growth of rust/crud inside the engine casting if the plug protruded inside, so there may be resistance to unscrewing for a longer time than expected -persevere! 20' - 30' Berths available, Clyde.
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