I'm hoping that I can get some pointers on what to look for in terms of hidden damage in the engine. We use this pump to water parts of our tree farm and had a strong rain about 2 months ago and it washed the pump from it's supposedly safe spot on high ground. The pump was in about 2 feet of water for over a week, when I found it it was about half full of sand and mud. I took everything that I could apart down to the bare block and left the pistons in place. Everything had mud and water in it but the gas tank. I used carb cleaner and parts cleaner to rinse everthing out and changed the plug and put fresh gas in it. It has the the low oil cut-off sensor and I had to disable that to get it to start( it was full of oil) it starts easily put now smokes bad and idles up and down on its own. I did replace the low oil sensor and hooked it back up. Could the water and sand have damaged the piston rings or cylinder maybe the carb. It was not running when this happened and was not started until it was flushed several times and the oil changed 3 times. I The first thing i did was pull the plug and spray wd-40 in the cylinder. Any help would be appreciated say from ( Restrorob) or others.