Sea Ray 180 temp indication varies excessively

[Iagent]

When I first picked up my year 2000 180 Bow rider 3.0, the temp would only be about 130-140. After using it for a while, the temp would consistently be around 175 every day. Yesterday, I churned up some muck in the river, and ever since, the indication has been 100-120. Other than that, no other symptomes. Has anyone else had a temp bulb go bad?

Thanks,
Rick

 

[Iagent]

UPDATE:

It's a faulty thermostat.
I am changing it, but can't get the plastic retainer out without destroying it.
Any ideas on this. See pics.

 

[mvoellinger]

Buy a new retainer, they are like $3 IIRC. I ended up beating the piss out of mine and was glad I had the extra one.

 

[Lazy Daze]

Pry it, spin it, etc, etc. Have another on-hand like Mvoellinger said.

 

[Iagent]

Got it! I made a slide hammer puller and just pulled at the thermostat itself.

I think I will get one to have on hand. Boating days are dwindling and don't want something like that to get in the way lol.

Thanks,
Rick