Got a question if anyone can help, I've been modding a 12' v hull, got it painted, wired with lights, started on the decking and seats-almost done. I bought the boat off of an older guy, the boat and trailer are in excellent shape, the day I took it home he put the motor down into a trash can filled with water and started it up. He adjusted the "lean and rich" knobs until it just purred perfectly. I did the same tonight, but I seemed to get alot of smoke on fast idle, there's an orange knob that screws in and out inside the "lean and rich" dial, what exactly does this orange knob do? I figured maybe air intake? Is this smoke normal just sitting in the back yard running? The boat is a 65 so I imagine the 6hp Johnson is just as old, the motor was maintenanced last fall, I have the paperwork. My First boat. Thanks

Wow a 66 Johnson, you don't see many of them now. I remember it as being a little 2 cylinder 2 stroke motor. So you mix oil with the gass at a mixture of 16 or 32 to one. 1/2 pint to a gallon of gass.

The low speed jets on the carbs are often air adjustments, and as you turn it CW it will make the mixture richer. The high speed adjustment is  fuel metering and as you turn it CW the mixture will get leaner. It takes a little practice to get these adjusted just right.

If the gas/oil mix is correct the motor will smoke at all speeds. The oil in the gas is burned with the gas, and hence the blue smoke. Use 2 stroke oil and it will be less noticible.

Johnson used to put a slow speed adjustment, that basically set the idle speed, and made no changes in the mixture. But this was usually a knob on the front of the motor. So if it requires a screwdriver it is probably a lean/rich adjustment. Have fun with your motor....

Thanks bro! If you or anyone, could instruct me on how to post photos on this site, I have plenty of them of the boat and motor, would love to post em!   Thanks again!   D.