If you want to eliminate the gauges, disconnect both sending units and
temporarily run a wire from the cool motor to the one showing hot and one
from the hot motor to the one running cool. If the problem now shows on the
one that was running cool, you know you have a bad gauge.

--
Bill
Chesapeake, Va


"Eldon Cutlip" wrote in message
m...
If I remove the thermostat from the one that is running hot (or at
least hotter), should that then duplicate the cold one - with the hand
test? And if so, that should prove the guage is the culprit?

Thanks,
Eldon

trainfan1 wrote in message
...
Eldon Cutlip wrote:
I recently purchased a boat that has 2 1986 Johnson 70 motors on it.
On the first run out we noticed that the temperature guage for one of
them went up to the top of the red while the other stayed in the
bottom 1/3rd of the green. We stopped the motors and took the covers
off and put our hands on both of the heads near the spark plugs. The
one that had stayed in the green was barely warm and the one that was
in the red was hot enough to bother your hand if you left it resting
on it for 30 seconds. We had actually never gone more than about 1/3rd
throttle on either engine for no more than about 5 minutes. And the
one in the red had only been at idle except for about 30 seconds when
I had put it up to about 1/3rd throttle. The pee stream on both motors
looked good. But on the one that was in the red, the pee stream was
even stronger - actually stronger than I have ever seen on outboards.
I replaced the thermostat because I was thinking that the impeller was
good because the pee stream was so good. But it still climbs up to the
red after just a few minutes at idle - and then the powerhead feels
hot to the touch - not like it burns your hand - but again
uncomfortable if you leave your hand on it for a while. Any ideas what
the next step should be? I called the local boat guys and they are all
at least 2 weeks out and halibut season opens Thursday - so I would
like to get a chance to use the boat before 2 weeks from now.


Thanks,
Eldon

If you can hold your hand on it for 30 seconds, it's actually running
cold. It sounds like the gauge is inaccurate. There was no factory
provision for sending units on these engines except for the warning horn
switch, so the installation is suspect, too.

A count to about -6- before it gets too hot for your hand on the
thermostat housing is normal operating temperature. Maybe the pee
stream on the colder engine is weak because the thermostat is stuck open
or someone has removed it.

Rob