View Full Version : Yamaha 25hp 2 Stroke water in cyl

10-27-2009, 06:41 AM
"I just bought a 2004 25hp Yamaha. One cylinder had low compression. After tearing it down the low cylinder had water evidence but the top cyl was nice. Would this be a cracked block or maybe a bad head gasket? I bought it cheap so I want to rebuild it. Unfortunatly i dont know the history other than it was used alot, and often. Also, what years and hp's swap to this motor? How many lower units fit this year and horsepower? The shift lever is also really sloppy, so I am not sure if the gearcase is working correctly, but this will be a winter project. Thank you for any advise."

10-28-2009, 03:27 PM
"Check the head gasket for evidence of a leak at the bottom cylinder. (Low compression + water)
Be this the problem, You got an easy cheap fix!!!"

10-28-2009, 08:25 PM
The head gasket does look badly corroded between the cylinders.