115 Inline 6 Temp Sensor and Over Temp Switch Questions

[justchecking]

I'm putting a 1984 115 Inline 6 onto my new to me bowrider. I would like for both the temperature and water pressure gauges on the boat to work as well as the overtemp warning buzzer. The old boat I took the motor off of had only a water pressure gauge, so the motor apparently does not have the temp sensor or overtemp switch. I searched the parts diagrams for the sensor that goes next to the number one cylinder but haven't found a part number. Would that be for a sensor or switch? Is there anyway to get fit both on this motor? Does anyone know the part numbers?

I've attached a pic of the sensor hole next to no. one cylinder and also the water pressure tap.

 

[carholme]

Re: 115 Inline 6 Temp Sensor and Over Temp Switch Questions

checking:

here is the parts lsit for that engine:

http://www.crowleymarine.com/mercury-outboard/278.cfm

See item 26 in this link which is the temperature switch, which would go next to the sparkplug:

http://www.crowleymarine.com/mercury-outboard/parts/278_15.cfm

Here is an idea of the many types of temperature sending units which are available:

http://img853.imageshack.us/img853/255/teleflex20sender20insta.jpg

Hope this helps and is not too confusing.

Gerry

 

[Chris1956]

Re: 115 Inline 6 Temp Sensor and Over Temp Switch Questions

Most if not all of those inline six motors do not have a thermostat. A temp gauge is useless since they run dead cold at idle and warm up a bit at speed. I recommend you skip it as you will not see a reading unless the motor overheats. The water pressure gauges are a pretty good idea. The inline motors have only a low pressure so don't get your hopes up too high.

I though the cost of the overtemp sensor was outrageous, BTW. I would look to adapt something from the automotive world. All the idiot overheat lights on cars have an overtemp sensor driving them.

 

[justchecking]

Re: 115 Inline 6 Temp Sensor and Over Temp Switch Questions

Thanks carholme and Chris1956.

I saw that switch yesterday "Switch - No Picture - $170.41". I thought for sure that couldn't be the temperature switch. LOL.

None of the gauges worked on my last boat. I'm trying to get every gauge working on this boat.

Anybody know of specific sensors/switches that can be adapted? The gauges are all 1991 Sea Ray which I think are Teleflex.

 

[Chris1956]

Re: 115 Inline 6 Temp Sensor and Over Temp Switch Questions

All the gauges will work. The temp gauge will be useless, but will work. The tach will work. If you have a trim sender on that motor then the trim gauge will work. They do not work too well however. What other gauges do you have?

 

[justchecking]

Re: 115 Inline 6 Temp Sensor and Over Temp Switch Questions

Tach and volts work. I test ran on muffs yesterday.

Temp Gauge would work but Chris1956 is correct, the inline 6 puts out cold water (actually 80 DegF during the test) so actually no reading on the gauge. Maybe I'll put the water pressure gauge in there.

Speedometer. Haven't hooked it up yet. I need to pull the lower unit and check to see if the nipple is there. No tube runs up thru mid section. I plan on using the motor tube if possible because the old boat had LOTS of holes drilled in the transom and rot. This one doesn't.

Overtemp buzzer. Not working yet but I did find the correct sensor at 1/3 the price. I'll check out the circuit and hook it up. I hope it never goes off.

Fuel gauge almost works. Needle gets stuck on full fuel when I turn on the key. I can un-stick it then it works. I put in another gauge from the old boat but it reads low. I need to make some measures of the sender output. Maybe I can disassemble the old gauge and fix it. Looks likes it's glued together so will take some finesse. The gauge I put in is a Teleflex. Except for the Sea Ray face plate the gauge I took out seems identical so I'm not sure why they would read different.

The old boat had a trim sensor which never worked. No trim sender.

 

[justchecking]

Re: 115 Inline 6 Temp Sensor and Over Temp Switch Questions

Speedometer: I pulled the lower unit and found the nipple was there but no hose. I put on a new hose and ran it up through the center pivot then to the front of the motor. Hooked up to the existing speedo tube. I used my GPS to check accuracy of the speedometer. Results were:
Boat Speedo GPS
50 47.5
40 38.5
30 27.5
20 18

Not bad considering one is a small hole, water pressure, coiled tube, needle and the other one requires several satellites, antenna, receiver, sophisticated math, LCD display.

The fuel gauge does seem to be working correctly. Over temperature switch is hooked up and checked out. Water Temperature gauge is working, during the full speed test runs cooling water in was about 70 and heated water out was about 110 according to the gauge.

I will probably install the water pressure gauge this winter. I would have to drill a hole in the dash and not sure where I want it.