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Dnord
My 2002 Johnson 90 horse just started running sporadically.  To me it seemed like a fuel issue.  I took it in for repair and they tell me it is a bad thermostat on the LH side of the motor (motor is achieving 170-180 degrees).  They tell me that the electronic computer picks this temp up and puts it into what they called a "slow mode".  But if the thermostat is not the problem than it is the computer which is very costly.

I am very frustrated with this diagnostics, mostly because I do not understand how this just happened from one day from the next but also being I do not have a clue to 2 stroke engines.

Does this sound like a logical explanation or am I getting taken?

Thanks  Dave
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marinermikes
If your motor is reaching 170 to 180 there is no doubt it's overheating.  Tjhe first thing you need to do is to get it to run the right temp.  Changing the termostat would be a good place to start but you would also want to check the water pump.
There's a sensor on each head for temp. If either one of them goes overtemp you will go into slow mode.  On your particular model I'm not sure if it goes throught the computer.  The older models had a tan wire that goes to the spark pack that put it in slow mode.  Either way you must first fix the overheat problem.    Mike
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Dnord
Mike

Thank you for your replay.  Two new thermostats are on order and will be installed shortly.

Hopefully by this weekend.

Dave
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marinermikes

Let us know how it goes.   Mike

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Dnord
So far the water pump, fuel pump, carbs all check out ok.  Still waiting for the new thermostats to show up.  Will the computer reset itself out of the "slow mode"?

Need to get back on the lake before the cold and ice show up .
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Dnord
Motor is fixed, just needed the new thermostat. 

Thanks
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