1994 Mercury 50 triple tstat, 120 or 143

[hevysrf]

I see 2 tstats listed for my 1994 mercury 2 stroke, 120 and 143 degree, which one should I use? thanks MartyD

 

[carholme]

Re: 1994 Mercury 50 triple tstat, 120 or 143

Marty;

What is your s/n?

Gerry

 

[hevysrf]

Re: 1994 Mercury 50 triple tstat, 120 or 143

OD 243955 are the numbers on the freeze out plug, name plate long gone. Thanks MartyD

 

[Faztbullet]

Re: 1994 Mercury 50 triple tstat, 120 or 143

The 50hp uses the 143? and the 60hp the 120?

 

[hevysrf]

Re: 1994 Mercury 50 triple tstat, 120 or 143

Thank you very much.

 

[hevysrf]

Re: 1994 Mercury 50 triple tstat, 120 or 143

Where would you install a water pressure gage tap ? There is a plug near the top cylinder,or should it tee in with the telltale stream hose? MartyD

 

[sxmerc]

Re: 1994 Mercury 50 triple tstat, 120 or 143

Water pressure gauge gets hooked up at that plugged port on top of the cylinder head.

 

[hevysrf]

Re: 1994 Mercury 50 triple tstat, 120 or 143

I'm still getting overheat buzzer at idle on hose, new water pump, strong tell tale. Water pressure very low at idle. Block temp measured at temp sensor with thermocouple about 180 at idle, drops with increase of rpm. Looked at poppet vale diagram shows two parts missing from mine, #16 carrier and #17 grommet.
Ordered parts, new carrier has a bevel on it that I can't see on the parts diagram, does the bevel go towards the block or the tstat housing? Tell tale is cold, does that pass thru the tstat or does it come off before it? Is a water flow diagram available for this engine? Thanks, MartyD

 

[carholme]

Re: 1994 Mercury 50 triple tstat, 120 or 143

Marty;

Which thermostat are you using?

Here is the manual for your engine and if you look under Powerhead, page 4-3, item 27, it calls for a thermostat of 120 degrees.

As well, if you look under General Specifications, page 1-22, you will have the values for the water pressure test.

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/817643r1/cover.pdf

Gerry

 

[hevysrf]

Re: 1994 Mercury 50 triple tstat, 120 or 143

Well, my manual is a little different, part # 90-817643---1, but covered serials are the same, tstat is item#6 on 4-3 but no temperature spec is listed. The poppet parts I oredered are design I, don't physically fit, so I'll try design II with a 120 stat. Faztbullet sugested the 143 and I confirmed it opens 143 on my stove. Thanks MartyD