How Hot

[cklages]

I checked my 89 70 horse Johnson with a laser heat gun and it showed 159-162F for all three cylinders is that good? I was running it with muffs what should it be running at?<br />Thanks Chad

 

[rickdb1boat]

Re: How Hot

Depends. Was that at idle? At idle you should read 140* +- 15*. This is after running the engine at 3000 RPM's first for 5 minutes and then letting it run at idle for 5 minutes. At 5000 RPM's is should read no more than 160*. When was the last time you replaced the impeller is the real question?

 

[Solittle]

Re: How Hot

I would think about 140 but check your manual.

 

[ob]

Re: How Hot

My dealer carries a 163 degree thermo melt stik.If it melts when touching the head covers or block,you got a cooling issue.I think your running borderline,assuming you had adequate waterflow while flushing.If you don't know when the last waterpump kit and T/stats were replaced,I'd address it.