Need help identifying

Sounds like you are talking about the "thermostat". Contact Zach at N3 Boatworks and he will get you the part you need. They oftentimes get stuck in the open position allowing water to circulate constantly when it is not always needed.

That's definitely not the thermostat. Looks like the sending unit to me.

Shagit, that is a temp switch for an overheat alarm. (buzzer) it is wired in series with the oil pressure switch. Neither one effects the gauges. It has nothing to do with the temperature gauge.

Look at the wires: The sending unit that controls the dash gauge should be solid tan in color. The wire for the one you pictured will likely have a tracer stripe. Dead give away.

From behind the dash, with the key "on" take a jumper wire and connect the gauge sending terminal (S) to ground. The gauge should peg full scale. (unless its a VDO) If the gauge pegs then the instrument is fine and your troubles lie in the wiring or sender.
If the gauge does not jump then you have a power supply issue or bad instrument.


First clue is to watch the gauge when you turn on the key. Does it wriggle at all? It should at least set to zero with a bad wire or sender. Check purple for power with the key on. A test light is much easier for this than a VOM if you happen to have one.
The above applies for the fuel instrument as well.They work on resistance to ground.

Shag take a breath.
Remember this: Gauges and senders must be a matched pair. Apples and apples.
Teleflex, Tempo and all the other stuff normally found on these boats will peg full scale when grounded.
VDO is backwards to that.
If I take a VDO temp / oil / fuel gauge and apply the sender wire to ground the gauge will read full low scale or (zero)
IF I leave the sender wire adrift and un-grounded, it will go full scale.

Methinks you have a Teleflex sender talking to a VDO gauge. Thats like me asking directions in Cantonese to a man from Portugal..

Apples and bananas...

Zing.... Glass seeker...:)

Hey how do you guys feel about removing the thermostat totally? Just curious

shagit wrote: The sending unit, from what everyone says, is the one I already replaced on the intake manifold next to the thermostat housing. There is two on these boats, one a sender and one a switch I'm told...

That sounds about right. One Temp Switch and One Temp Sender.

Does this boat have Protec? That temp switch pictured above could also be for the computers SLOW mode.

The thing is though, this switch won't (as far as I know) have any effect at all on what you see with your gauge.

I had a VDO temp gauge that I was fighting with. Fixing shaky grounds and wiring in general improved it somewhat (It was always reading very high, higher than my infrared temp gun indicated), but just replacing it was the final solution.

Grounding the sender wire, like Baitkiller said, will let you know if it's working.

Another good overheating troubleshoot guide is this one from Skidim. It applies more to actual overheating rather than electrical problems, but still a good short read:
http://www.skidim.com/Faq_TROUBLESHOOT.asp#RWTS

shagit wrote: Now to find white face vdo gauges.... Hmmm

I had to use Farias for mine. If you go the Faria route, they are no longer spade, they are ring and post. So, you'll have to get a decent crimper and some new terminal ends. Not a big deal, just not quite plug and play.