1968 65hp SportFour Carb Question!

[nuttyboater]

I had a chance to browse through a service manual for this motor while at a marine store today, unfortunately i couldn't talk them into borrowing it out for a weekend.. lol

Anyway, i didn't understand the carb adjustments reading the manual. This motor has a dual downdraft carb as i'm sure most of you already know, and there is two knobs on the front, one for each side, its kind of a pointer type knob.

I sorta understand the manuals directions for setting these needle adjustments, but the question is are these knobs mirrored? Let me explain. It says how i should set both of them to a certain point to begin with, half open i think it was but where would that be, if i have them both with the pointer pointing out to the sides, which is about half the available travel between the stops, would that be roughly the same opening of both sides?

That would make one side a left hand thread since one side would be clockwise to close and the other side would have to turn counterclockwise to close.

Confusing right??

 

[F_R]

Re: 1968 65hp SportFour Carb Question!

Stop trying to make sense out of the knobs. They come off and can be installed in any position.

The threads are both right hand. Turn clockwise for lean and ccw for rich.

Make you adjustments for best idle running, then remove the knobs and reinstall them in whatever position suits your fancy. The factory put them pointing in opposite directions as you noted.

 

[nuttyboater]

Re: 1968 65hp SportFour Carb Question!

Ok i see!!

Thanks a million for clearing that up! I have prior carb knowledge from working on snowmobiles, chainsaws, lawnmowers, snowblowers, you name it, but when i read through the service manual and then came home and looked at it i got confused since the knobs limit the amount of travel due to the raised bit on the carb.

I found a post on here this morning, searched back through some posts that were years old, and i found a mention of removing the knobs and setting the needles to about 1 1/2 turns from lightly seated, then after making the final adjustments just replace the knobs wherever you want.

So now i got two people telling me the same thing and i have somewhere to go.. lol

On another note, isn't it interesting that when it comes to working on carbs its always that magical 1.5 turns to start? Same thing on the chainsaw carb i just rebuilt.