[v12mac]

Yamaha 250hp 4stroke Kicking water out exhaust relief port
The other day I noticed a buddy’s Yamaha 250hp 4 stroke was kicking out a lot of water through the exhaust relief port on the back of the motor at idle. Usually I see some splatter but this thing was kicking out about as much as if you were to dump a full beer out over the exhaust port. Is this normal? (The water not the wasting of a perfectly good beer.) The motor was apart in the last year due to an overheat.

Ideas?

[DMSOUTH]

Sounds like the pressure relief valve is stuck open.........

[v12mac]

I am not an expert on this motor, is that a big deal? Can he run it like that for the season? This motor's cooling system was packed with sand and that caused the over heat a while back, any chance this could have been missed in the rebuild? or is it packing up with sand again?

[DMSOUTH]

Should be checked before running it much--at idle the prv is closed, allowing cooling water to reach the top cylinders. At higher RPMs, the valve opens and dumps excess water. If stuck open, the upper cylinders will overheat.

[v12mac]

Thanks, I'll politely tell him to get it checked. But, you know the old "F-it! It is under warrantee" mentality....