A welsh plug is a soft metal dished plug that is inserted and expanded in place by lightly tapping on the crown. It is commonly used to plug holes.
The Welsh plug in the yoke is no longer sealed. The yoke will need replaced.The Welsh plug in the yoke is no longer sealed. The yoke will need replaced.
fouled plug(s) or carburetor icing
Your lawn mower spark plug may be wet due to excess fuel in the engine or a faulty carburetor. To fix it, you can try cleaning or replacing the spark plug, adjusting the carburetor, or checking for any fuel leaks in the system.
This is typically caused by a stuck or faulty float valve in the carburetor. Usually a good carburetor cleaning will take care of it. At the worst you will need to replace the carburetor.
Carburetor float is stuck open.
Incorrect timing or plug wires connected incorrectly.
If you're lucky, there should be a drain plug for the float bowl (the bottom portion of the carburetor). Put a rag or something under the drain plug and then remove the drain plug, letting the gas/water flow out onto the rag. While you're at it, you may want to flush the carburetor with CRC Carburetor Cleaner, or something comparable. Give the cleaner time to evaporate, then put the drain plug back in. (Note: older outboards can have high speed needles where the drain plug should be. You can remove the needle, just make sure when you put it back in, it is in EXACTLY the same configuration it was in before. Also, DO NOT screw the needle in all the way to where it "bottoms out," as this may damage the needle permanently.) Water in the carburetor is NEVER good, and MAY require you to rebuild your carburetor to make sure that any corrosion/gunk has been thoroughly flushed out.
If your asking about FREEZE OUT PLUGS then it has 8 of them.
a welsh plug is a plug in the side of the block and the heads. these fill the holes left after casting.they actually allow the sand to be removed that is used during casting so as you have a hollow block which allows for the water jackets. in the USA these welsh plugs are called freeze plugs. they really do not stop the coolant from damaging the block if coolant freezes they are specifically to block the casting holes
The fuel mixture is probably set to rich. Also, the wrong spark plug (with regard to heat range) could be in the engine. If you have an adjustable carburetor with mixture adjustment screws, try turning the screw (probably located on the bottom of the carburetor, in the middle of the bowl) inward 1/8 to 1/4 of a turn. This will lean the mixture. If you have a no-adjust carburetor, then there is not a lot you can do to change the mixture. Try using/replacing the spark plug with the correct spark plug as recommended by B&S. Good luck!
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water freezes and expands popping the welsh plug