Overheating - help!

2017 Craz - replaced the impeller a week ago and ran great for 2-3 days (~10 hours) then Sunday shortly after anchoring in a slightly weedy area got a DTC 116: ECT higher than expected stage 1 error message. Temps climbed up towards 225f so I shut it down and idled back to the marina. I don't know if it's impeller related or perhaps I pulled up some garbage in the raw water line.

I don't see any leaks on the impeller cover.
I do NOT have a raw water strainer (lesson learned - will add now) - I pulled off the hose connected to the raw water shutoff and did not see any signs of debris.

If debris is the issue where else should I look? Tranny cooler? If so where?
If impeller any ways to test that it's working properly?

Shop is 2-3 weeks out so I'd like to keep digging into potential options while I wait and to hopefully avoid missing a big part of the MN season.

Could definitely be the impeller, I know there have been bad batches, just take it out and make sure it looks like it did when it went in.

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