So to update I ordered the Hardin SS pump housing with their impeller and wear plates. It is installed now and it seems to be doing the trick - temp has been stable at 160F last 3 outings so I think the problem was cavitation (even though the pump housing really didn't have that many hours as...
The impeller is probably too easy to turn and I think I didn't have to compress quite enough to close when re-assembling. I may just go ahead and order a new housing and I am thinking of the Hardin SS housing that people have been recommending -
Another longshot - there are 3 air hoses connected to sea water pump. 2 are vacuum hoses and there was another hose that was larger and not a vacuum hose and went straight up and was pinched off (in other words, did nothing?). The fitting for that hose got dinged during my pump removal so I...
Old impeller came out intact but there were a few small chips missing but I am assuming that shouldn't be the problem as it ran beautifully up until I changed the impeller. The old impeller also still seemed quite pliable and had about 200 hours on it (just about the interval they suggest)...
I did preventive maintenance to change impeller myself - used non-OEM Sierra to replace previous Sierra impeller that lasted over 100 hours with no problems and no previous overheating. Boat alarmed (high temp) on 1st outing after changing impeller.
Pulled belt and turned pump by hand and...
I think you're right and hopefully Amazon will catch up with them because they can see the return stats the problem is I wasted about 2 weeks trying to isolate whether it was the part or the way I installed it so that was wasted time unfortunately. I had seen the mechanical differences but...
Update: I ordered the Mercury OEM part and installed it, RPM came back to normal range (600 rpm). Returned non-OEM part. Not to imply all non-OEM parts wouldn't work, but the particular brand/one I ordered certainly did not!
Yes switching to the OEM part worked and when I started up, the idle came back to its normal range (approx 600 rpm). I bought the OEM part here (https://www.boats.net/product/mercury/862998).
Ron H.
I replaced my original IAC (after getting alarm code and rough idle). Used non-OEM (Sierra https://www.amazon.com/dp/B07JVHJMZF?psc=1&ref=ppx_yo2_dt_b_product_details). Seemed very straightforward. Part fit beautifully, motor started up and sounds great, also took test run everything fine...