'89 dt25c water out exhaust port

[sgtmajorbrad]

I bought this motor years ago and finally got around to getting it running. The person I got it from said it needed parts to get it running. having made or procured the parts I took it out on the lake and noticed that water was pouring out the exhaust. I pulled the thermostat cover, hooked up a hose and water went out the intakes and the exhaust. By looking at my service manual and the water flow diagram water out the exhaust doesn't seem correct. The motor also stuttered at full throttle with the idiot light matching the frequency of the stutter. Before I pull the heads and the exhaust cover I'd like to verify my suspicion before moving the motor back off the boat. Any help will be greatly appreciated.

[Solarman]

Yes, water can go out the water pump intakes, and exhaust if you hook a hose up to the thermostat opening?
I don't know why you would pull the heads?
Water is pumped up the midsection through the exhaust cover to the thermostat, and through the block to the tell-tale (pee hole), the remaining water goes back out the exhaust. When the thermostat warms up then more water should flow around the cylinders to keep them cool, then through a small pressure type flow valve (the faster you go, the more water is pushed through this valve) in the water jacket at the bottom of the heads. You should not need to pull the heads to clean this valve (if this valve sticks open, more water will flow out of that exhaust at the back of the motor.), but each head should have this by-pass valve in the bottom. Most of these by-pass valves are just a small ball and spring that block/slow the water going straight out the exhaust hole. It is probable that your valve(s) is/are stuck open from corrosion, sediment & lack of use.
The exhaust cover plate is just that, it covers the exhaust from each of the cylinders (this exhaust gets extremely hot, and there is a water jacket that keeps water flowing over this exhaust plate, to cool the exhaust). This water ties into the pee hole, the thermostat, and then goes back out with/through the exhaust at the prop.

Hope this helps you understand a little more.

Good luck.