I have been having trouble with my speedometer not reading. I have cleaned out the pitot tube and when I blast water from my garden hose into the pitot tube, it sprays where the yellow connector attaches to the outdrive. If I hold the connector, the speedometer moves to about 20mph. The yellow connector was a little worn and did not seem like it was holding in place. I purchased a new yellow connector from mercruiser parts and connected it. I have not tested it yet (cold outside) but am wondering if an o-ring is suppose to be on the end of the yellow connector. The new one did not have one and neither did the old, but I read on another site, the o-ring was important. The end of the connector that sits inside the drive looks like an o ring would fit on it but the inside of the housing seems to big or bigger then the hole that the connector fits in. The new one fits tighter. Maybe it will work. I need my wife to watch the speedo when I use pressure on the pitot tube because I can not do both I also have blown it out from the speedometer connector to clear the line. Really curious about that o ring. Thanks.