mystery water

[whippersnapper]

i have an '87 70hp yamaha, i found that my lower piston had gotten water in it. causing the piston to score heavily. i cannot find where the water is comming from at all. the engine was just rebuilt 23hrs previously. all gaskets were seating perfect. no blown head gasket or cracked head. there was no water in carb either. any feedback appreciated.

 

[whippersnapper]

Re: mystery water

 

[waterbill]

Re: mystery water

Try a possible lower crankshaft seal leaking. There is always a vacuum in the crankcase, and if the seal is bad the water will get in and go to the lower cylinder when the piston is in its intake stroke. I learned this in an outboard repair class. The instructor also said to check the spark plugs for the lowest one having rust--indicating that bad seal. I'm no expert, so any of you experts out there please correct me if I am mistaken.