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1966 Johnson 9.5 Low Speed mixture screw removal???

C

CMOS

Regular Contributor
Howdy All,

My 9.5 has been running like a scalded dog for the last 1.5 years. Lately however the idle is experiencing that rough "cough" where the motor shakes. I have been slowly adjusting the mixture screw more rich over the last 6 months however the rough idle is to the point where richer does not solve it (nor dies leaner...).

I'm hoping I can remove the mixture screw and use some Carb cleaner in this part of the idle circuit to clear it up. However, even with service manual I can't figure out HOW to remove the mixture screw. The manual says TO remove the screw but not the how part. This is the old style with the flex cable going to the front control panel.

Other than the rough idle this motor is starting and running like a champ. And yes, great and equal compression on both cylinders.

Can anyone help me with this?

Thanks,
CMOS
 
Pull the knob off the front. Now look behind the panel and see the E-ring around the shaft, against the panel. Slide the E-ring off. Now it is possible to slide the needle/cable forward to remove the C-ring. With that off, you can slide the cable aft, out of the front panel, then just unscrew the needle/cable.

But maybe all you need to do is pull the knob off and then you can turn the needle more toward "rich".
 
fdrgator said:
Pull the knob off the front. Now look behind the panel and see the E-ring around the shaft, against the panel. Slide the E-ring off. Now it is possible to slide the needle/cable forward to remove the C-ring. With that off, you can slide the cable aft, out of the front panel, then just unscrew the needle/cable.

But maybe all you need to do is pull the knob off and then you can turn the needle more toward "rich".
Click to expand...

There is no e-ring on mine. So if I pull the knob away from the front panel, the knob will disconnect from the cable, correct?

CMOS
 
Sam110 said:
Yes the knob is splined and will pull off the cable but without the "e" clip securing it to the panel you'll need to hold it from moving.

Your problem (cough/sneeze) sounds like a familiar issue I was having with my 71 9.5 last summer. Have a look through this Post, it might help.
http://www.marineengine.com/boat-fo...er-plug-removal-9-5-9122R&p=550700#post550700.
Click to expand...

Okay, thanks. Interesting thread. After I get things cleaned out I'm going to install a fuel filter between the QD and fuel pump like my 15 HP has.

I will work on it this weekend. Thanks for the info. BTW - I can't find the darn e-clip anywhere. MarineEngine.com - nope. Boats.com - nope. Etc.


CMOS
 
Yes. I know the part number, but nobody has had it.

Ha! Just checked MarineEngine.com - they have it!

CMOS
 
Last edited:
The E-ring is a standard hardware part. If you have a decent local hardware store, try them. Yeah, I know, decent hardware store are a rarity these days.
 
Good success today. I was able to pull the low speed mixture screw, and shoot in some carb cleaner. I also installed a fuel filter to hopefully help present this in the future.

While I was at it I also decided to dump all the remaining fuel in the tank and mix a new batch. I do this about every 7-8 tank fills to prevent any possible compounded error in fuel-oil mix rate.

She's purring like a Kitten. Started on the first pull. One small adjustment to the low speed screw and now she set. Nice smooth idle again.

Thanks for all the help.

CMOS DSCN7150.jpg
 
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