How Hot is Hot

[helesh]

I have a 87 Mariner 150 that

I have a 87 Mariner 150 that shows barely out of the good range on the temp gauge. All the likely fixes with impeller etc have been done. We've shot the head with a digital thermometer and it never goes above 155F. The alarm works and has never gone off. Still that gauge is disconcerting and it's almost too hot to keep your hand in the water stream. Oh yeah changing prop pitch had little to no effect. So how hot is too hot?

 

[tonyob]

"Helesh,

You might have a s

"Helesh,

You might have a small leak in a head gasket or exhaust manifold gasket. This could cause the water to heat up.

Did you check the thermostats?

"

 

[helesh]

" Thanks for the reply Tony. Y

" Thanks for the reply Tony. Yeah, originally we drilled out the old thermostat then later replaced it. So what's going on here? Is the head getting too hot or just the water. If there is a small leak must it be fixed ASAP? Money's tight!
Les "

 

[tonyob]

"Les,

When you say that you

"Les,

When you say that you drilled out the thermostat, it leads me to believe that there may be some debris blocking one or more water jackets. I would remove the heads and exhaust manifold and check for blockages. You will probably have to remove the water jacket covers on the heads also.

"