I have a older Donzi that I purchased and the water temp guage has never worked. I want to figure out why. I traced down everything and I am down to either a bad guage (new guage) or the wrong temp sender (more then likely this). If I short out the wire from the sender the guage will max out so I think the guage is fine. It will never read any temperature when running and based on readings I took with a temp gun it should be.

The guages are newer Merc. factory guages. I have no idea what the sender is. I know that they can be different depending on what guage you have. Anyone know what sender it should be?

if the sender is in the thermostat housing try grounding the outside of the sender with a wire to the battery and check the gauge..If it works then you may have the wrong lower gasket..the replacement has 4 brass rivets that ground the housing..you would think it would ground through the bolts but after years of corrosion they dont do as good as a job..

The sender is in the intake manifold just to the starboard side of the T-stat houseing.

Heres something to read while your up this late sir.

http://www.donzi.net/forums/showthread.php?t=56580

And another. You might find something.

http://www.donzi.net/forums/showthre...ht=temp+sender