Is it my T-Stat?

Glassguy54

Had the boat out this weekend and the temp gauge was not reaching normal with in the expected time frame. Running at 3500-3800 RPM, the needle barely came off its perch. I took it up to 4800 RPM and ran for approx 20 min. and reached normal temp. After slowing back to 3500-3800, temp fell to below normal again. Does this seem like its a thermostat? What is the procedure for R&R? Remove all hoses from housing, undo bolts, lift T-Stat out, replace with new, then what? Do I need to add water to system for initial prime? Is raw water cooled BIII, 350 MAG MPI.

MarkB

It's pretty easy. The most difficult part is scraping off the old gasket sealant. Once it's clean just pop it in add gasket sealant and put int he gasket. Reassemble and you're good to go. 

I didn't have to reprime. The raw water pump pushed the water through immediately. 

youstolemybeer

More that likely something is jamming the stat open.   Mine gets rocks and pebbles stuck in it all the time

MarkB

Just remember the risk of running too cold is the engine runs rich thinking it's in start up mode. Unburnt fuel can then find its way into your oil, diluting it, which is not good for lubrication. Check your oil level, if you find it is climbing, that's why - and you need to change it ASAP.

Glassguy54

Thank you all for the excellent advice and guidance. We weren't planning to go out this weekend, so I'll investigate.

Michael T

.....and I keep getting bizarre information regarding then proper engine operating temperatures for my 2014 8.2 Mags. One time it should be 165F for a catalyzed engine, another time its should be 170F. I have no friggin idea who is correct. I can look at my mercury manual for 2014 - but that would be the one that tells me I MUST use FULL synthetic oil in my 2014 8.2 Mags.....wait a minute , disregard THAT  - don't do that any more - now you must use a synthetic "BLEND".  Merc.  just mailed me the new manuals for  my new engines with the wrong data in them - call your dealer for the new bulletins - nice! So, at this point when I look in my manuals or talk to some Merc techs I have no idea if they have any clue what the data should REALLY be. To me it is very frustrating. I wish Al lived closer!