damn it we just can’t seem to catch a break when it comes to the engine overheating. We went out for a fireworks show and on the way back we started overheating. Fortunately, idling down to 3 knots boatspeed kept the temp under 200 so we were able to get home.
Clearly, we have reduced cooling capacity. A complete failure of the cooling system would be much easier to fix–it would be far easier to find the problem. This reduced capacity could be cause by any number of things.
I took some video of the water coming out of the exhaust, so I could hopefully get someone to tell me whether it looks satisfactory or not. Of course, when we’re actually underway this probably changes (I know at times the dribble coming from the anti-siphon vent disappears).
It could be something to do with our water heater plumbing. I’ve heard terms like “airlock”, and heard plenty of stuff about needing to bleed from the highest point, but I don’t understand what is up with our setup. Here are some shots for people to look at:
The Valiant Owner’s Group had tons of great suggestions, which I compiled:
1. prop fouled–try cleaning prop
2. strainer outside boat clogged; remove hose from sea strainer and see how fast the ocean comes into the boat (should be quite alarmingly fast)
3. sea strainer could be clogged beneath the basket even though it looks clear–take it off and run something through to check
4. the gasket on the cap of the sea strainer may not be air tight–we might be sucking in air as well as water
5. oil cooler could be partially plugged
6. even partial blockage in heat exchanger could cause the problem
7. cam in seawater pump may be worn out (difficult to tell by looking it it with amateur eye)
8. impeller might be sheered between hub and blades, even though it looks perfectly fine
9. gauge might not be properly calibrated; get an infrared thermometer to check
10. fragments may be lodged in hoses or exit from raw water pump, or heat exchangers; remove hoses and sight down them to double check, try flushing with garden hose
11. clamps on raw water side might be loose; anything allowing air to be sucked in will mess up the cooling
12. back plate of raw water pump may be worn out–check to see if there is noticeable wear or grooves where the impeller has worn into the back plate
13. cooling system may have an air-lock, especially with the hot water heater installation; try bleeding air from petcock on top of heat exchanger (is that high enough to take care of it?)
things we already checked
-thermostat could be the wrong temp, or not working properly
-heat exchanger, oil cooler, tranny oil cooler could be scaled up
The next thing to do is run down this list I guess. Really excited about that.
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