1994 70hp carb question

boydog40

Petty Officer 2nd Class
Joined
May 15, 2005
Messages
126
what is the correct setting on the slow speed needle screws? do i close them all the way in and back them out? if so how many turns back out?
if not how do I do it?
thanks
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 1994 70hp carb question

get it running, then work one carb at a time:

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

tedious

Petty Officer 2nd Class
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Nov 26, 2008
Messages
133
Re: 1994 70hp carb question

Just to double check how this all works for a multiple carb motor, in the first part of the procedure, I'm working all the carbs at the same time? That is, leaning out each one 1/8 turn until I hear the first sneeze?

Tim
 
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