I took out the plug of Tecumseh 7hp L-head that has been sitting around since last winter. Most of the time it was loosely covered with a tarp but at times uncovered.
Today I took out the plug to do a compression test and the piston top had water on it. The only way I can figure water got in there was condensation through the valves. It rained a bit last night and this morning so moisture probably came through the valve area. It makes an interesting case because if I looked in there after a few good days the water would probably have been gone. I’ll bet water has been cycling in and out of the head for several months. Not so good for cast iron bores and rings.
Someone might argue that they’ve looked in 50 engines and never seen water. I’ve looked in more than 50 and the first time I’ve ever seen standing water on a piston top. It makes a good case for drawing up the piston to the compression stroke on storage especially if your storing outside.
