inconsistant temp readings plz read on

[tryme]

i just put in a new defender impeller this year and a new thermostat.  i am getting temp readings of 160 to 200.  doesnt really go any higher but not sure why it is spiking and coming down.  i dont think it is the impeller as it is brand new.  i am going to put in the old thermostat and test any one have any other ideas?

[lilfoo2225]

i was kinda having this same issue before. i narrowed it down to voltage spikes. the gauge will read perfect if i dont have the blower or heater blower or shower on. but i always noticed it reading high then normal after turning off the blower. have you watched the temp with nothing on? not even the stereo? but id say if thats not the case id check into the temp sender unit. seeing that you replaced the thermostat already. good luck cause i know how these boats can be with those gauges.

[wakejunky]

+1 for lilfoo. trying turning off all your accessories and recheck. I'm currently working on the voltage spike issues. Ive managed to reduce them drastically but there is still some electrical interference. ill hopefully figure it out soon.

Also did you use a factory thermostat? make sure its a 160 F not a 180 F

[tryme]

That was it.  turned everything off and bam 160.  now how do i find my voltage problem? just keep everything off? 

[wakejunky]

What year and model boat do you have?