what is the USUAL operating temperature???

[bob johnson]

I finally got a second temp sender...

one head settles in after a good amount of warm up at about 130 degrees..

the other head settles in at about 165 degrees


before i react...id like to know the NORMAL range the motor is supposed to run at.

i have good water pressure( got a gauge and a tell tale)

is it possible that one thermostat isnt opening???

will the head not go higher than 165 with a thermostat that isnt opening??

I can remember watching the lower head run up to about 140 and then fall back to 120 and then settle in at about 130...all makes sense for the T stat that opened.

I THINK cant remember actually watching it...that the other ran up to about 175 and then fell back to 160 and then settled at 165

but I may be wrong..

can it be that it is PARTIALLY opening only??

is it possible i have more friction on that bank???

the spark plugs are all the same

1995 Johnson Ocean Runner 115 hp( 60 degree looper)

thanks

bob

 

[Chris1956]

Re: what is the USUAL operating temperature???

Normally thermostats open at about 140*F. it sounds like you shuld test yours. Hang them in a pan on the stove, so they do not touch the bottom. Heat the water and check it with a candy thermometer. They should start to open at 140. Or just replace them....

 

[Vic.S]

Re: what is the USUAL operating temperature???

It would also be wise to cross check the two sensors with each other

 

[bob johnson]

Re: what is the USUAL operating temperature???

It would also be wise to cross check the two sensors with each other

I originally only had one sender so i took turns running the boat with it screwed into each head, and got the same readings as i got with BOTH senders installed( i did that to verify that both senders are the same! even though they have the same model number on them!!

I have a gauge wired through a swtich to check either head for temps.


bob

 

[bob johnson]

Re: what is the USUAL operating temperature???

I ran the boat today and I watched the temps.....if I milled around and low rpms and ran under 10 mph the temp in one head went up to about 190!!!! when i gave here throttle and got the rpms up to about 3000 and my water pressure went past 20 PSI( 10 at idle)

the temps dropped


then when i slowed back down....and kept it there the temps went back up in that head to 180 ish...

I saw the t stat open .. and it settled back down...but not much


one head runs about 130 degrees!!!

one runs around 170-180 when going slow and drops to less than 160 when cruising


do i have blockage in that head??? is my T stat not opening all the way


I am going to buy some new t stats any way and new gaskets


but in the mean time. I d like some help on why the temps go so high... and obviously react to more water pressure


which climbs to about 30 psi


thanks bob

 

[SparkieBoat]

Re: what is the USUAL operating temperature???

try removing the T-stat in that one hot head and see what happens..that will tell you if you have some kind of blockage in that head or not..or some other issue.

 

[fire7882]

Re: what is the USUAL operating temperature???

I'm not sure how the sender operates, but if it produces a change in ohms w/ temp change that is read by the gauge, the wires could be to blame. Might want to try swapping wires and seeing what happens. Also if you have an infrared thermometer, I would check the temp of each cylinder.

 

[bob johnson]

Re: what is the USUAL operating temperature???

I switched the T stats today and ran on muffs....now both heads run about 165 degrees



when i revved up in nuietral to about 1800 rrpm, the temps went to about 175- almost 180

water pressure stayed around 10 psi at idle ...

the rubber seats in the head appear to be different, bit the spring takes up all the slack, because one goes deeper than the other


I check them in water on the stove and they opened about the same time!!

didnt have a thermometer

bob