what is going on with my temp gauge

[todd goble]

vision 221 350 with alpha drive. last week temp gauge was reading 100 and this weekend it was reading all the way hot before I started the boat and when I started to run it, It started to go down and stayed at 180 and bounced to 200. I felt the exhaust and the manifold and only were warm to the touch. PLEASE HELP

 

[corey331]

Sounds like the sending unit might have finally had it.

 

[Budman]

impeller going bad can give fluctuations in temps

 

[todd goble]

Thank you both, I think my impeller is good and where is the sending unit located

 

[corey331]

I'm not really sure to be honest. But if I had to guess, I'd say in the intake somewhere.

 

[Budman]

mine is on the thermostat housing which might be another possibility of a sticky stat

 

[keith4216]

The guage is jumping with the motor off so impellor and thermostate are out. I think your going to be looking for electrical issue.

 

[Budman]

The guage is jumping with the motor off so impellor and thermostate are out. I think your going to be looking for electrical issue.

not necessarily so
UNLESS the gauge is bouncing all over with the key OFF
I'm assuming he means he turns the key and it reads hot and then cools down.
Water temps can increase when he shut the motor down and reads high when he turns the key on.
Actually I find his post confusing as to the sequence of events

 

[Budman]

I was clearly wrong before getting all the facts and offering opinions
I would tear into the electrical system

 

[Jimway]

Check and clean connections at battery. If that doesn't cure it, do a voltage drop check from battery to engine, paying close attention to cleanliness of connections at engine. If that doesn't cure it, ground sending unit wire and see what gauge does. Smoke is installed inside of the wiring in the vessel from the manufacturer. Do not let the smoke out...

 

[todd goble]

I am sorry for the confusion, the gauge seemed to bounce from 180 to 200 and at times it would drop to 160 and then go to 220 when I hit a wave. the gauge was pegged all the way before I started the enginge then when I started the engine and started to run it, it started to go down to 180 and then moved around. I hope this helps

 

[keith4216]

was the motor cold or hot when started
cold motor =electric
hot motor will have temp go down when started once the water starts moving thru.

 

[todd goble]

COLD not run for a week and the gauge was pegged when I turned the key

 

[miller]

Most likely the sending unit, or at least something electrical. Sending unit will be in front on the intake, in the thermostat housing or sometimes in one of the heads.

 

[todd goble]

Thank you to all of you for the help I will be checking the sending unit this weekend