New Northern Lights Genny - Problem

[Corbinkerr]

Hi All....I had a new M673L3.3G genny installed in the spring. It ran geat for the first 80 hrs, until I picked up a bunch of seaweed that clogged the sea strainer and killed my impeller. Ever since I changed that impeller the genny will run for about 10 mins but then shuts down. I'm suspecting its overheating but there are no gauges or lights to indicate shut down codes. I used the laser thermometer and it seems to be shutting down at about 195F.

I was worried more sea weed might have been trapped between the thru hull and sea strainer so I've snaked that and also from the output side of the sea strainer up to the impeller...Seems all clear. Its difficult for me to judge the actual outflow from the wet exhaust because that thru hull is right at the waterline, but there is a pretty good wake leaving that thru hull so I think the water flow OK.

I did remove all the hose from the impeller up to the heat exchanger and also removed the heat exchanger to remove all the impeller pieces that broke off....Its all clear.

I also flushed the coolant and re-topped it up. Also, did an Oil change just for good measure.

The only remaining thing I can think off is a faulty thermostat but that seems highly unlikely with only 88 hours.

Any other thoughts / suggestions?

tks
Corbin

[s/v Jedi]

I have the same unit. Test exhaust by catching the water in a bucket for so many seconds and see how much it is.

The thermostat is deep inside the exhaust manifold. It can also be the sensor that shuts the genset down at high temp.

I have the control panel with gauges… I think your wiring harness will have the analog sensor wires for temperature. You maybe able to read resistance and translate to temperature?

[skipperpete]

Hi Corbinkerr
After an overheat due to an impeller failure the first thing needed is a little forensic investigation regarding where the missing blades went, and how many actually are missing. The first place to look for them is on the raw water pump ports..... both the suction and delivery sides, then the supply to the heat exchanger end cap and finally ....the end of the tube stack under the end cap. It acts as a final filter. When you put the tubestack back into the housing make sure the air bleed hole in the casing is on the top.
Another thing to consider is that after an overheat the thermostat can be damaged, it’s just a wax pellet in a cylinder and during a decent overheat it can leak out of the seals ...same thing with the temp switch, it’s usual for a mechanic to change the thermostat after a damaging (dry) overheat. From memory the 673 thermostat is under the heat exchanger so not too hard to replace but make sure it goes back exactly as it came out, it fits either way but only one way works.
Excellent Genset by the way[emoji106]