johnson 150 cooling problems

[pioneer11]

I have a Johnson 150 95 that will not cool.
changed parts include:

impeller kit
head gaskets /silicone
t stats confirmed they open.
temp sensors

Have hooked hose to engine with stats out and water does circulate with no blockage.
compression is 110 in all six.
water pressure is good.
temp is higher in port 200+ star 190+
boat has two temp gauges that are new and it is indeed overheating.

 

[Will Bark]

Re: johnson 150 cooling problems

Have you checked the actual temp with an infared thermometer?

 

[71Windsor]

Re: johnson 150 cooling problems

when is it over heating? at an idle? while on plane? or havent you gotten it in the water yet? idle temps are higher always.

 

[pioneer11]

Re: johnson 150 cooling problems

checked heads with gun they are 200+ idles on hose hot and in lake hot. What is the idle temp supposed to be and wide open throttle temp?

 

[Will Bark]

Re: johnson 150 cooling problems

My 87 150hp idles with a temp of about 165 on both heads and have never checked it on WOT, Hopefully one of the gurus will chime in with other suggestions/tests. Good luck

 

[pioneer11]

Re: johnson 150 cooling problems

Bad thermo seals, idle temp is 145 both heads. thanks for the help.