500 efi temp sensor size

[EBT531]

I need to replace the factory temperature sensor which goes to the dash gauge with the proper gaffrig sender. Gaffrig offers them in several sizes, anyone know if the 500 efi takes a 1/2”, 1/4” etc?

 

[DaveH]

it has nothing to do with what the factory does. the merc 500 efi has its own separate temp sensor.

since you have gaffrig gauges, you need to speak with gafrig to get the correct sender. just because you get a certain thread size of what came out....doesn't mean the resistance range of the sensor is correct to work with the gauge you have if you just get any ol' sender that fits.

there are thread adapters out there to step down what is in your manifold if the port is larger then the sender.

 

[EBT531]

it has nothing to do with what the factory does. the merc 500 efi has its own separate temp sensor.

since you have gaffrig gauges, you need to speak with gafrig to get the correct sender. just because you get a certain thread size of what came out....doesn't mean the resistance range of the sensor is correct to work with the gauge you have if you just get any ol' sender that fits.

there are thread adapters out there to step down what is in your manifold if the port is larger then the sender.

I was going to order the sensor from Gaffrig, they just have several sizes so I wanted to make sure its the right one.

 

[LBZRCKS]

I just replaced both of mine. IIRC the one for the gauge is a 3/8" in a 1/2" bushing.

 

[Fun Times]

Merc OEM # 806490T, 3/8 in. x 18 NPT threads, used for temperature gauge, https://www.wholesalemarine.com/sender-water-temp-mercury-mercruiser-806490t.html

Item numbers 2 and 3, https://www.mercruiserparts.com/bam/subassembly/31341/7595/30

 

[EBT531]

Merc OEM # 806490T, 3/8 in. x 18 NPT threads, used for temperature gauge, https://www.wholesalemarine.com/sender-water-temp-mercury-mercruiser-806490t.html

Item numbers 2 and 3, https://www.mercruiserparts.com/bam/subassembly/31341/7595/30

Excellent, thank you