'97 Johnson OR 175 - Where is Needle Valve??

HS91_Mike

Seaman
Joined
Feb 11, 2009
Messages
62
I have looked at every diagram I can imagine of this motor and still I am not 100% on where these things are. I know that I have one per carb and I need to adjust them in sync while on the water, if possible. The motor has ran rich since I switched to non-ethanol gas. When I am looking at the carbs with the airbox off, which screw is the Needle valve? Is it a philips head or a allen wrench? Brass?

Thanks, Mike:confused:
 

HenryB

Petty Officer 1st Class
Joined
Dec 8, 2012
Messages
244
Re: '97 Johnson OR 175 - Where is Needle Valve??

Draw up a schematic of the carb from a parts web site.

It's the one with the spring.

The other is the one associated with the the float in the float chamber. It hangs from a tiny clip. No screw driver or wrench required.

Tweek it 1/8 turn at a time and wait a few seconds until you are satisfied.
 

HS91_Mike

Seaman
Joined
Feb 11, 2009
Messages
62
Re: '97 Johnson OR 175 - Where is Needle Valve??

I cant draw a diagram, I cant even draw a straight line with a ruler. Does anyone know what the carbs on a Johnson 175 looper (1997) look like and where the needle valve is located? There is a brass screw with an allan wrench fitting located on the upper left side of each carb intake. To adjust it, I have to stick the long part of the allan wrench through a hole in the plastic carb body. Is that the needle valve? Also another brass screw question - there is a small brass screw with teeth on it and a hole in the middle of the screw located on the upper part of the carb. I think it is labeled on schematics as an oriface. An oriface for what? Whats its purpose? Mike
 
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