Volvo Penta D4. Not Overheating but Underheating,!!

[jonboy1]

D4. Model Year 2005. 260 hp.

Went out today and on the way back one engine temperature dropped to 70 degrees,
Normally runs at 85 degrees.
I suppose it is the thermostat sticking open.
Any ideas.?

 

[VicS]

Thermostat
or temperature gauge or sensor

 

[Peanuts]

Before you do anything, do you know anyone whose has a infrared laser temperature gun and then compare the temperatures between the engines?
Well, thats what I would do anyway.

 

[grumpy_o_g]

Is it not possible to swap the senders easily?