- September 14, 2019 at 10:18 am #11348Christopher KirkParticipant
We recently had a serious engine overheating problem others might want to keep in mind. We have a NT32 with a Cummins 6BTA5.9.
We launched the boat after being hauled out at a yard in the Seattle ship canal. We idled to and through the Ballard Locks, but the engine overheat alarm came on when we increased RPMs as we left the locks. The through-hull was open and the exhaust appeared OK.
We idled a few minutes into Shilshole Marina and stopped. I called our mechanic, Auxiliary Engine, and he immediately said that our impeller had probably been destroyed from overheating. He had seen this before and was correct, He replaced it and the a section of exhaust line the next day. He said when the boat was hauled, water drained out of the through hull and hose up to top of the sea strainer, and the impeller could not overcome this air gap, at least at low RPMs. After replacing the impeller and cleaning out the pieces, he primed the strainer and through-hull hose before we started the engine, and it was fine.September 16, 2019 at 1:17 pm #11359Gary WhiteParticipant
I had that happen once as well on a different boat. From then on whenever I haul the boat I shut the through holes after shutting the engine off and before lifting the boat out of the water. I open them back up afterwards in the water and put my hand on the raw water impeller to make sure it’s not overheating before I move out. That has eliminated that problem for me.November 15, 2019 at 7:46 pm #11768Bill EplerParticipant
When I replaced the impeller on my 1998 32’NT this summer I discovered that the sea water strainer is mounted above the waterline. So opening the sea cock did not fill the strainer. I suspect that the stainer on this boat is also mounted above waterline.
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