I wanted to pull my thermostat and drill some holes in it to get boat to run a little cooler. Currently run 165 and will creep to 180 when running it. Would prefer 150. It has stainless marine exhaust and I have heard that they will run a little hotter with these. Any, how do you get the white plastic retainer out without breaking it? There is some corrosion in there. Secondly if I do break some of it getting it out but it will still hold the thermostat will it leak?
I pulled it off and the retainer doesn't want to come. Haven't broke it yet but I can see it happening. Wanted to try it tomarrow and wont have a new plastic retainer if I break it tonight.

Wiggle it it should come out.

im no mechanic by any means but having had a similar issue with mine, you may want to check - if you didnt buy it new - that there isnt some parts and pieces of an old impellar restricting water flow. obviously the previous owner of mine had one fail - and did nothing more than put a new one in and started boating again. the temp was doing exacly what you described. when i checked the water lines i found a bunch of peices stuck at my fuel or oil cooler - dont remember which one but all i did was clean that out and never had another issue.

good luck

+1^^^^
I can't put on the previous owner, it was me not clearing the lines after replacing the impeller.

The old one was overdue, and the new one helped but it still ran hotter than it should.

It still was creeping temp so I ended up going down from a 160 stat to a 140 stat. Now it run 140 and will go to just over 150 running wide open. Oil pressure is better too. Does anybody know what temp the cold start turns off? Just want to make sure it stays running clean. I also have the full MEFI tuning system, so I can change what ever I like if needed. We just turned off the chokes completely on my buddys 454 procharged boat and now it works great at low end.