Temperature problem

[cashworth]

Hi - I started my boat up today (Four Winns 205 year 2000 with Volvo 5.7Gsi, owned since new) on muffs ready for launch next weekend. As she was warming up at 1500rpm the temp gauge fluctuated about from cold to hot and then gradually settled on hot causing the alarm to sound. I tried this a couple of times with the same result. I took the thermostat out and still had the same result. I tested the themostat and it opened in nearly boiling water. When I put it back I didn't connect the up the sender on the thermostat housing and still I got hot readings on the gauge!
Part of me thinks that I hav'nt got a problem as its to do with running on muffs as the boat was fine when last run but does anybody have an idea whats going on?

Thanks in advance,

C Ashworth

England

 

[Don S]

Re: Temperature problem

When was the last time you replaced the impeller in the raw water pump?

Those impellers should be replaced every other year.

 

[cashworth]

Re: Temperature problem

Hi Don - Thanks for the quick reply. The impellor was replaced last year and I am getting a good flow of warm water at the transom when running on muffs. What I can't understand is why the gauge gives a reading even when I disconnect the plug on the sender on the thermostat housing - surely it should read zero? I will run the engine tomorrow in a tank instead of muffs to see if I get a different result.

Thanks

C