Logo
FULL SITE MENU

2000 Mercruiser 4.3 190HP 2 BBL Carb Operating Temperature ? Glastron GX185

GlastronGary

GlastronGary

Member
Hi,
Can anyone tell me what is the normal operating temperature for a 2000 4.3 Mercruiser? My temp gauge is always at 170 - 175 F during normal running with the lake/river water temp about 69 - 73 F. Recently I was heading down river and was in a hurry to get back so I was running near WOT at about 4250 RPM (49 MPH) for about 15-20 minutes straight when I heard a warning alarm (short horn about 2 seconds) my temp gauge was about 182 F, I slowed down to about 3200 RPM for the remaining 15 minute ride and had no problems with the temp gauge at 172-175 F.
I'm not sure what the normal operating temp should be or at what temp the alarm is supposed to sound.
Can anyone help me out?

Thanks in advance
 
WHat you most likely have is a 160 degree thermostat.
Also the over temp switch is most likely a 180 degree set point.

What this means is you may need a new impeller in the outdrive as it cannot supply enough water at high rpms to maintain the normal operating temp.

Merc manual says 160* thermostat.

If the temp switch is border line on max temp

Water temperature switch, # 48952 Opens at 150-170°F (66-77°C) Closes at 190-200°F (88-93°C) The alarm is active when closed

Water temperature switch, # 87-86080 opens at 175-195°F (79-91°C) Closes at 215-225°F (102-107°C) The alarm is active when closed

No I am no expert on alarms..........so first make sure it is a over temp alarm.

If you have a temp switch (tan or tan with blue wire typically passenger side of thermostat housing) and it goes off again, unplug it and if alarm goes out then it is a over temp alarm.

To test temp switch, simply unplug and jump wire to ground with key on. This should reproduce alarm/beep to see what type of beep it is.

Make sure it is not the temp sender that will PEG the gauge!!
 
Back
Top