96 SN GT-40 Thermostat

I discovered the thermostat on my 96 SN is probably the original. It was rusted and in bad shape, but miraculously still working. So my question is do I need to replace it with one that is exactly the same as the one I pulled out? Or can it be one from Napa autoparts that not "exactly" the same, but fits the engine and is 160 degrees. My mechanic friend says it doesn't matter as long as it fits and has the same temperature rating. See pics..First one is from Napa.....

I think I got mine from Nautique parts, a forum supporter. Had to wait a couple days but it works perfect.

I think you might want a 143 degree thermostat. Not sure, hopefully someone else will confirm which should be in your engine.

JD,
Since the stat was still working, what was it that caused you to open up the housing to find the rusty stat?

In answer to your question about why I checked it even though it was working:
1. I just got the boat last fall at the end of the year and I have been checking all kinds of things as I think of them, and I was winterizing and pulled the hoses and the housing.
2. I had a mastercraft that almost stopped running and I pulled the thermostat housing and the thermostat was so corroded it didn't even resemble a thermostat. It looked like a twisted rusted chunk of metal. So I always have that vision in the back of my mind.
Btw: I am sure it is the 160 degree thermo for the efi gt40 it has run at 160 consistently all summer and I did a bunch of research on it too. Thanks everyone for chiming in.

Hollywood wrote: A 160 thermostat will result in the engine running 170-175 A 142/143 thermostat will result in the engine running 155-160 Your mechanic friend is right in that a thermostat is a thermostat. If it fits it's right and simply choose the temperature you want.

I guess that's why I mentioned maybe 143, didn't mean to give bad information. My '98 with GT-40 runs 160 on the gauge and from prior reading here I knew that had to be a 143 stat. So, I don't know if my boat had the wrong stat when I bought it, or it's right, or what the story is.

No idea. I installed a heater a couple of years ago and have good heat once the boat is warmed up, even at idle, even in colder water temps this time of year. So, I wouldn't change to a 160 for the heat. I guess my view is that a marine spec engine running 160 or 175 would have little difference in performance and wouldn't affect engine longevity, I'd be more concerned that the engine gets up to temp, holds a temp, and doesn't run more than a bit above that temp in all operating conditions.