Trojan Boat Forum

Let me first explain my exhaust system. The exhaust on this boat is based on the Bertram Velocijet system. The exhaust and raw water are sent to a common muffler system where they are separated. The exhaust fumes are discharged out the side of the boat, while the hot raw water is sent down a hose to a thru-hull in the bottom of the boat. Since you cannot check the exhaust to see if your raw water pump is working, Trojan placed a sensor on the raw water system in the event your raw water system was malfunctioning.

Yesterday I had the boat put in the water and the alarm sounded. At idle the temp spiked on my starboard motor. I pulled my raw water pump and the impeller looks perfect. My coolant level was low on both motors and I added quite a bit of additional coolant to my heat exchanger and coolant overflow jug. The overflow jug was sucked right up by the port (non-problem) motor, but not the starboard motor with the overheating issue.

Since the raw water alarm is sounding, I assumed it was that side of the system. Now I'm thinking its might be the freshwater side. I'm a bit confused. My next step was to pull the raw water hoses leading from the heat exchanger to the exhaust manifold and see if water is flowing while the engine is running. After that, maybe my thermostat, but that wouldn't explain my raw water alarm. Oh, and my hull bottom screen is clear and my raw water strainer is clear and bubbling when the motor is on. I think my raw water sensor is at the end of the exhaust just before my muffler system, as this is the only place that I could find a wire.

Todd , I don't know what Trojan used for a raw water alarm on the 10.8 . But I will try to help . First are you sure its a raw water alarm going off and not the engine alarm ? Now assuming it is the raw water alarm , then it can be pretty safe to assume a raw water flow problem is causing your over heating .

Check the water flow of course , make sure the raw water pump belt is tight and not slipping . Look for ant signs of water leaking at the pump both shut off and running , as a bad seal will cause the pump to suck air and lose prime or reduce flow .

There are other places to look but I am assuming the boat was fine until it was put up for the winter .

Good luck

Oh buy a temp gun to compare engines for temp .

prowlersfish wrote: <snip>

Good luck

Oh buy a temp gun to compare engines for temp .

=============================================================================

+1

The IR Temp Gun is will allow you to compare and isolate the problem quickly.

Also, not expensive anymore.

TWS

Temp gun it is...I'll let u know how it goes. Thanks guys!!!

Do you have a "U" shaped oil cooler on the front of the engine? They are known to clog up. Pull both plugs on it, one should have an anode. Sometimes an older anode will break apart, block pasages in the cooler and reduce flow. You can try checking flow before and after the cooler. May be hard to see a small difference but if you see a notable difference, that may be the problem.

Big D wrote:Do you have a "U" shaped oil cooler on the front of the engine? They are known to clog up. Pull both plugs on it, one should have an anode. Sometimes an older anode will break apart, block pasages in the cooler and reduce flow. You can try checking flow before and after the cooler. May be hard to see a small difference but if you see a notable difference, that may be the problem.

Yes, there is an U shaped oil cooler. I will add that to my list. Thanks for the help.