trainfan1 wrote in message ...
Eldon Cutlip wrote:

I took the thermostat out of the "hot" one and then ran it on the
"ears." The engine stayed dead cold for as long as I ran it (probably
a few minutes). But the pee hole just dribbled a drop or so every few
seconds - no stream. Then I put the thermostat back in and it had a
good stream at the pee hole but the engine started heating up again.
Should I still get a good stream even with the thermostat out - if the
water pump is good? I know the powerhead was getting water because it
stayed dead cold and I saw water when I pulled the thermostat cover.

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

With the thermostat out the pressure will fall off. Hence my suspicion
of your "cold" motor. The thermostats should be closed, or
substantially so, until around 150 degrees, and then they will let 150
degree or warmer water by. You can test them on your kitchen stove with
a candy thermometer if you must.

Where are your sending units?

Rob

I don't know where my sending units are. For the Mercury engines I've
had I always got a nice shop manual for the specific engine from
Mercury. I haven't had a chance to get one for these Johnsons yet. I
do see a wire coming out of the power head just left of the thermostat
that I was guessing might be it.

I was thinking that even with the thermostat completely removed that
the pee hole should still have a stream of some kind - so I was
thinking my water pump was suspect. Are you saying that with the
thermostat completely out the pressure is reduced enough so that the
pee hole may just dribble (with no stream) and my water pump may still
be good?

If so, maybe I should just replace the thermostat on the cold one and
see if it "warms up?" If it does I could then do a "hand test" to see
if they are both pretty close to the same heat range? And I could
also see if their guages start reading close to the same heat range?

Unfortunately these thermostats are weird plastic ones that I've never
seen before and I don't think I would be able to see anything if I
boiled them. And more unfortunate is I won't be back home until
Friday evening to continue working on this.

I really appreciate your help. I haven't really even got a chance to
try this boat out because of this problem and I'm really dying to. I
did schedule an appointment in 2 weeks with the mechanic. But the
sooner I can get it worked out the sooner I can try out the boat

Thanks,
Eldon