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Gregory McGuire
 
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Default 1986 Johnson 70 Overheating

hi eldon,
when mixing oil for 2-stroke 100 to 1 means you used less oil and less
protection to the engine and runs hotter. For instance I run 50 to 1 mix of
2-stroke oil. So in a gallon of gas is 128 ounces of fuel.
At 50 to 1, I mix 12.8 ounces of marine 2-stroke oil for 5 gallons of fuel.
I have a mixing cup to measure my fuel mixture. (128 divide by 50 = 2.56
times 5 = 12.8)
I think I am correct.
greg
"Eldon Cutlip" wrote in message
m...
I replaced the water pump in the "hot" engine. So, that meant I had
replaced the water pump in both engines and thermostats in both
engines. Someone else had already moved the pee hole connector to the
top of the exhaust housing on both engines. And someone else must
have already upgraded the springs on the thermostats. Because the kit
said I should just replace the straight spring that was in there with
the same straight string in the water pump kit. So I think I should
be good on all the water pump conversion things.

I then ran both engines (at idle on the ears) and they both got into
the red on my guages. The laser gun showed up to about 135 degrees at
the front of the thermostat housing and up to about 170 degrees
(varying though) at lower parts of the power head. So I decided I
better take it to the local professional before I screwed things up.
The mechanic called and said both engines were running great. He said
they were both below 150 degrees and that they ran them up to 2000
rpms. He said he believed the sending units on the guages were bad
because they looked pretty corroded. He said he was going to see when
he could get some in and maybe look at getting me set up with water
pressure guages instead (he thought they would be a better indicator
of a good cooling system - and I still have the overheat warning
horn). But then he called back later and said they do not make the
sending units or guages for my motors anymore. He cleaned up my
sending units and replaced them. I took the boat out for the next
three days and the motors appeared to work great. No overheat alarm.
When one of the guages got up into the red the corresponding motor
appeared to be smoking more than when the guage showed in the green.
I was wondering if that could have something to do with the fact that
I mixed the gas in the tank 100 to 1 as a safeguard because I was
afraid the guages going in the red might be because the mix was too
lean. Does that seem possible at all? Also, do any of you guys know
what the part numbers for the sending units and guages would be and
where I might be able to find obsolete parts like those? My motors
are 1986 Johnson 70hp - model: J70TLCD I bought a parts manual but it
doesn't seem to include part numbers for the sending unit and
temperature guages.

Thanks very much for the help!
Eldon