Dirty carb... or something else?

[Beefer]

1959 Johnson QD-20 10hp.

Starts great, runs great, but there are 2 things amiss. 1. Won't idle at the lowest throttle setting 2. Low Speed Idle Adjustment knob unscrews when running from the vibration.

Where do I start, what do I do?

The cheap and lazy part of me just wants to run seafoam through it for a few tankfuls.

 

[HighTrim]

Re: Dirty carb... or something else?

If the carb has never been cleaned, it might be time, the carbs are very easy and straightforward.

There is a packing nut that tightens with a 7/16" wrench which keeps the needle from moving. Just tighten it up and the needle will be tight again.