Engine raw water cooling flow

[Charlie]

I just bought part ownership in 1979 Oday 28 with 15 hp 2 stroke engine. This is my first boat with an inboard and raw water cooling. Out flow from raw water cooling exhaust seems very spordacic. Diver has made sure intake filter screen is clear. Is this normal and possibly caused by pressure building to push water over anti-syphon loop? Is there a way to back flush the system?

 

[Jim Cook]

Occassional spitting & splatting is normal

Charlie,I have a '74 O'Day 27 with 13 hp Volvo diesel. You are right about the mixing of exhaust and water sputtering out as it is pushed over the loop. It doesn't take much water to cool the engine (I'm not sure if this is true about gas engines). However, I have had an occasional blockage in the intake line.Here's what my neighbor taught me to do.1 Check the size of your rubber line going into the water pump and buy the same size female end connector for a garden hose.2 Disconnect the line going into the water pump and push the garden hose connector into it. 3 Connect to a garden hose and hold it while someone turns on the water.I like to have air in the garden hose so that I can hear it bubbling up outside the hull.Please note that I have a Volvo saildrive unit, but this should work for you, because my neighbor has a regular drive unit. It is cheap, easy and effective.Congratulations on your new baby.Jim Cook"Dream Chaser", O'Day 27

 

[Mike]

It's O.K.

I too have an O'day 28 with a two stroke Zephyr OMC (now Bombardier) sail drive engine. The intermittant outflow of cooling water from the engine is normal. The higher the revs, more water; lower revs, less water. There is a warning buzzer built into the ignition switch at the switch to warn of overheating. Look under the lazaret seat just to the left of the lazaret opening and you will see the wiring and the buzzer. Mine has never gone off but I assume it is loud enough to hear over the engine noise. Don't worry about low flow. It's normal.Mike