Evinrude Yachtwin 8 water pump wierdness yesterday

[RobG]

While returning from a sail yesterday I lowered the motor (it tilts up out of the water) and fired it up to enter the river to my mooring. As I happily (or unhappily - hate the motor) chugged along all of a sudden I was shocked and pannicked to see barely any water streaming from the water pump pressure check tube. I lowered the RPM and continued as it is a very buisy channel and kept my fingers crossed. Back at the mooring I tilited the motor up and checked all of the intake ports, the streaming tube and the cylinder temp. All seemed normal. Since it was cocktail time I was going to leave it for another day so it sat out of the water for a half an hour. Well it finally got to me and I had to check it further. I lowered it back into the water and fired it up. The water pressure was now fine. High and low RPM. I let it run for a few and it kept working. Is there such a thing as vapor lock or a priming prolem with OB's? Has any one heard of an impeller being loose on the shaft so it is intermittant? Could deposits be nearly clogging the system? The water out there is pretty free of dabris and I saw no sign of blockage.

 

[Rich Stidger]

Check your impeller

Things happen for a reason. I had a similiar problem with my engine.Last year at layup, all was fine. Pumped a solid stream of cooling water.This year, first time out, almost no water. I found upon disassembly that I had a small piece of a previously replaced impeller stuck in the output tube from the powerhead and it was blocking the flow.It could be that your impeller has broken a piece off and is lodged in a spot that SOMETIMES blocks the water.

 

[Pete]

could have been

a clog,sometimes the salt water will leave deposits. and it will clog the streaming tube. I would try at again and keep a eye on it. Since the engine did not overheat I would not be overly concerned about it unless it happens again.If possible give the engine a fresh water flush after using.

 

[Chris Burti]

Probably not the impeller

It is unlikely that you have an impeller problem, they are usually all or nothing.It is fairly common for the P-tube to become obstructed on these small block outboards. Lots of reasons; impeller pieces, salt, seaweed, mud, wasps etc. If you have a reduced flow in the future, test the output temp with your finger, if it isn't hot to the touch, it probably isn't an impeller problem. Back feed it with air or water pressure when you get a chance and it should clear up. If you continue to have intermittent problems, You will have to pull the foot off and blow it out from the pump end.Another reduced flow problem with the older engines is from excessive shaft wear at the seals. This is rarely intermittent and will require a new shaft.