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70 HP Johnson low speed idle adjustments

S

sglass

New member
I took my boat down to start it up from the winter (engine fogged and fuel system cleared) Idle was rough even after cleaning out the storage smoke. Looked in the manual for proper method to adjust and set the idle screws at 2 1/2 turns out after a light seating. started engine, it started and ran very rough. started adjusting the idle screws per manual and finally got each carb to smooth out. Now my question is the idle screws are now only approx. 1 full turn from being set. Why would i need to start at 2 1/2 turns and only get smooth idle and performance at 1 full turn.:confused: By the way the year of the engine is 1991.
 
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That 2 1/2 turn out is the default setting to get it running, you just fine tuned it at 1 turn each, then apparently that's the proper setting for your particular motor.
 
MikDee said:
That 2 1/2 turn out is the default setting to get it running, you just fine tuned it at 1 turn each, then apparently that's the proper setting for your particular motor.
Click to expand...

According to my manual, one of the carbs takes 2-1/2, the other takes 1.. So I guess you have the latter.

Just make sure you are not making it run lean. It will run fast and smooth, and tend to "pop" a little. That would be bad. Too rich much better than too lean.

-TH
 
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