2000 Mercury 90 Saltwater 2stroke Thermostat

[fishnutz]

Hi All, been awhile and then I couldn't log in, but thats all better now thanks to the great moderators!

So, I am wondering if this is a big job or not? I will be down by my boat for only a week in October to start the season and want to replace this as well as the impeller(been there, done that). I have never tackled the T-Stat before. Any special tools? Approx time for average wrench?
Thanks In advance!!

Rob

[Blue Agave]

Very simple job, to replace the two t-stats on my motor takes me approximately 20 minutes.  A box wrench is all I need to do the job.

[fishnutz]

Holy Chit that was a fast response, Thank YOU! Do they come as a kit w/ gaskets/seals?

[GoneFission]

Holy Chit that was a fast response, Thank YOU! Do they come as a kit w/ gaskets/seals?

Good question!  In fact, check the plasic bag.  Sometimes the stat will come with the rubber gasket and sometimes not.  Mercury often does not include a gasket and Sierra usually does.     If you are ordering - consider ordering a gasket anyway.  That way you will have a spare if you ever need to check the stat for blockage.   It's a pretty easy job, but take your time and clean out everything you can as you disassemble so you don't clog up a nice new stat.

See ya on the water!

[Blue Agave]

You're welcome!

As Capt n John mentioned take your time. If this is the first time the t-stats have been removed the bolts might need a little convincing.  When re-assembling a little grease or anti-seize on the bolts will help on future t-stat inspections.

[fitz73222]

Holy Chit that was a fast response, Thank YOU! Do they come as a kit w/ gaskets/seals?

PM me with your email address and I'll send you some pages out of a factory service manual for the part views and part numbers. Easy job on a 90 HP as long as no stuck bolts. 13mm box wrench, use only 1 hand on the wrench to break them loose. wire brush the threads and scrape the mating surfaces well. clean with acetone. Order the parts from ISHOP MARINE, select the parts based on your engine serial number, it will start with OG, OT, etc. Thermostat, seal, mating cover gasket. I'd replace the entire poppit valve assembly if it's original. Mercury perfect seal is the best for bolt threads and mating surfaces. DO NOT USE NEVER SEIZE on anything on an outboard. It is metallic based and will lock up when exposed to salt water.

Fitz