1995 150 temperature Guage sensors

[Fl_Richard]

I've got twin 1995 150 motors that used to have simular temperature readings. I'm trying to get them simular again.

The problem motor has a new water pump housing,& impeller. (As does the good motor.) They have been always saltwater used and rinsed religiously. They look like new. No corrosion anywhere. They both pee a good solid stream of warm water. Water pressure is around 5 psi at idle and slightly under 30 at WOT (5900RPM) on both engines.

One currently shoots to 160 degrees in idle speed zones then drops to under 120 (end of gauge) while on a plane. The other (the one that hasnt changed behavior) Runs 120 in the same idle speed zone and and rarely goes over 150 at anytime; and runs around 120 while on a plane. I dont think I've ever seen it 160. I tested both engines thermostats, they ALL open fully at 165 (IR temp meter pointing thru water). I replaced the caps, thermostats and springs two years ago as preventative maintenance.

BMC has temperature sensors P/N584152 & 584589 at a $100.00 a set!!

Can I test my existing ones?

 

[clanton]

Re: 1995 150 temperature Guage sensors

The first thing I would check, is both engine have the correct waterpump housing. The sensors you listed are only a on-off switch that set the overheat alarm at around 200 degrees F. Engine should idle about 150F and run 120,130. Thermostats should start to open at about 140F.
The waterpump housing is easy to install the wrong one. You should find correct pump by model number and BPR parts manual

 

[Fl_Richard]

Re: 1995 150 temperature Guage sensors

Done that. They are the correct pumps and housings. I'm good about that stuff.

Are you sure they are only on/off type switches? these are not the sensors with the tan wire attached. I thought Tan wiring was over heat alarms. The engines have one sensor on each engine with a tan wire. These wires come out of a small plastic grommet on the head. If you take out the grommet the sensor slides out of a perfectly fitted sleve in the aluminum.

These sensors have brown with blue stripe and white with blue stripe. (I think... Color blind)

Help the handycapped!

 

[clanton]

Re: 1995 150 temperature Guage sensors

Thats them, the sensor on the port side with the two wires works the quickstart system. more after I find my manual.

 

[Fl_Richard]

Re: 1995 150 temperature Guage sensors

I've got a OEM Manual. The terminology is a bit cornfusing...

Is the guage temperature sensor the one that sticks 1" out of the head on the starboard side with a nut holding the tan wire on?

Edit -- Your suggested temperature settings are almost EXACTLY what my "Good" starboard engine reads.

 

[Fl_Richard]

Re: 1995 150 temperature Guage sensors

Bump^^^^

 

[clanton]

Re: 1995 150 temperature Guage sensors

The last post about guage sensors is correct. The two part numbered sensors are for overheat, S.L.O.W and Quick Start. Starboard side sensor with tan wire is over heat, closes about 203F and sets the overheat alarm. I don`t have my manual yet and can`t tell what the wire color is on the port side. Use the LT meter and insure both are running at correct temp, point LT at thermostat housing for readings. If engine are ok the work on guages. If you have an OEM manual, the wire color code and temps are there,