water temp guage all over the place

[wrestler20]

Hello, just a quick question to help figure something out. I have a 92 200 johnson gt and i am more used to automotive engines than outboard engines. I have an outboard temp guage and a water pressure guage installed. Is the temp guage on an outboard supposed to work like an automotive temp guage, because mine goes up and down from extreme to extreme depending on my rpm. The impeller and water pump were replaced last year as were the thermostats. Now an automotive engine gets to operating temp and then stays relatively at the same temperature. Mine outboard temp will range from way up by the warning for hot when i idle for a while and then run all of the way down to cold when i am running on plane. Is is supposed to do this? If not, what should i look at? thanks, <br />Steve

 

[Backlash]

Re: water temp guage all over the place

Hi Wrestler20,<br />Did the gauge do the same thing before you had the t-stats replaced? The temperature shouldn't fluctuate that much while operating. In fact, it should stay pretty constant once up to operating temperature. Sounds like the 'stats aren't functioning properly.<br />Backlash

 

[wrestler20]

Re: water temp guage all over the place

I put in the gauge after i had the stats replaced last year, so i don't really have anything to compare before and after, sorry<br /><br />Steve

 

[Backlash]

Re: water temp guage all over the place

Check out everything connected to the gauge to ensure nothing's loose, etc. If your motor isn't actually overheating, then your gauge must be faulty.<br />Backlash

 

[clanton]

Re: water temp guage all over the place

Should idle between 150/160, Just as the rpms go up the temp will drop, maby as low as 120. After about 2000 rpms, the water pressure pushes the thermostats off of there seat and the water bypasses the thermostat. Not like an automobile.

 

[Freezebear]

Re: water temp guage all over the place

Funny, I thought I was the only one witht that same problem. Mine is a 92 60Hp Tracker. I just installed new water pump, thermostat(was missing), and new gauges over the winter. I took it out a couple of times and mine runs about 1/4 gauge while idling. If I put the boat under load and don't plae out and keep RPM's anywhere between 2000-4000 the gauge goes up almost to the red zone. If I throw the throttle down and increase RPM's from 4000-6000 the gauge goes down to 1/4 gauge again. I was told this was normal and have made several open water runs with it and have had no trouble overheating. i did verify that my overheat system actually worked. You should too. Check by grounding brown sensor wire at the sensor connection. Also remove sensor and put in boiling hot water for a few seconds to test continuity.

 

[clanton]

Re: water temp guage all over the place

Freeze, there was 4/5 service bulletins for your engine, most for overheat and over cooling. Search this site for bulletins, If you installed an OEM water pump kit, it would include 2 of them. The temp sensor you checked should have a tan/blue stripe pig tail. If tan only needs to be changed.

 

[Freezebear]

Re: water temp guage all over the place

Thanks Clanton, fixing to sesrch for the bulletins now. Yes, I did have to do some things to the motor when I installed the new water pump. It told me to pull the restrictor out from the pee-hole and run the hose straight out with a little bushing to hold it in place.<br />Also had to put a different spring in the thermostat housing.

 

[Freezebear]

Re: water temp guage all over the place

Uhh! Where do I find the bulletins? I can't find them anywhere.