Temperature rating for thermostat on 5ltr efi merc

[geardownthreegreens]

As per title.
Does anyone know the operating temp for a thermostat in a 5ltr merc yr 2000.
I've read a range between 143-160 f and the new one which replaced the last one is 180f or 82 c Is that too high a temperature to open?

 

[gordmac]

82c would be in the ball park (maybe on the low side) for a car engine, can't see why a boat would be different.

 

[Alrob]

taken from mercruiser online manual


80
CA788
Engine Specifications
(V-8 Models)
Models 5.0L 5.0L EFI
Propshaft Horsepower 2201 2401
Propshaft Kilowatts 1641 1791
Displacement 305 cid (5.0L)
Maximum rpm @ WOT3 4400-4800 rpm
Idle rpm in NEUTRAL3 650 rpm5 600 rpm6
Oil Pressure @ 2000 rpm 30-60 psi (207-414 kPa)
Min. Oil Pressure @ Idle 4 psi (28 kPa)
Thermostat 160° F (71° C)
Timing @ Idle rpm4 10° BTDC 8° BTDC
Firing Order 1-8-4-3-6-5-7-2
Electrical System 12-Volt Negative (–) Ground
Alternator Rating 65 Amps
Recommended Battery
Rating
Minimum
375 cca/475
mca/90 Ah
Minimum
550 cca/700
mca/120 Ah
1 Power Rated in Accordance with NMMA (National Marine Manufacturers’ Association)
rating procedures.
2 Power Rated in Accordance with SAV 1 rating procedures. This rating procedure
is used to certify that the engine complies with “Stage 1” Bodensee and Swiss Regulations.
Horsepower differences shown result from differences in test RPM, allowable
test tolerances, and/or installation of special kit components.
3 Measured using an accurate service tachometer with engine at normal operating
temperature.
4 A special procedure must be followed to check or adjust timing. Consult your
Authorized MerCruiser Dealer before attempting this procedure.
5 A special procedure must be followed to adjust idle RPM. Consult your Authorized
MerCruiser Dealer before attempting this procedure.
6 Idle speed on EFI models is not adjustable.

 

[Its_Only_Money]

That range looks good in F - boats engines run cool to avoid salt crystal formation which occurs at car-like temps....

 

[geardownthreegreens]

Many thanks guys and alrob for that technical info there.
looks like the stat i took out to check was working properly was set too high.
According to that data, 71 c is the temp it should be set too,not 82c.
I'll hopefully be meeting an engineer on my boat Thursday afternoon so i'll ask him before i place the old back.
Once again, many thanks.Si

 

[jhr]

My 5.0l Merc efi runs at about 170 F according to the gauge, and always has done according to the original commissioning test-run carried out by the dealers. The thermostat was replaced this year - and it's still reading 170. Not sure if this is because the gauge is mis-reading a bit or because I've got the wrong thermostat. The former, I think, because the Yard swear blind that it's the correct stat for the engine.

Always runs very happily and no alarms, sign of damage from operating at an excessive temperature or anything else, so I've always reckoned if it ain't broke.......