1969 Evinrude 55hp selectric shift carburator questions

kal22378

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Apr 29, 2010
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Ok so i was thinking about cleaning out the low speed valve and the high speed plug, is there a general rule for adjusting these screws? I mean do you screw them all the way in and then back them off so many turns?? If so are they the same? Another quick question. Would shifting have anything to do with the vacuum diaphragm?
 

Joe Reeves

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Re: 1969 Evinrude 55hp selectric shift carburator questions

(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 1: 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.

Note 2: If the engine should be a three (3) cylinder engine with three (3) carburetors, start the adjustment sequence with the center carburetor.

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.

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The vacuum diaphragm...... if it's faulty, replace it. It's purpose, as I remember it, is to keep the engine in neutral until the engine stops running.
 

kal22378

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Apr 29, 2010
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Re: 1969 Evinrude 55hp selectric shift carburator questions

Hey thanks for the response Joe, My vacuum diaphragm was cracked and noticed a little bit of a oily substance leaking out of it so i popped it off and super glued a cut down bearing buddy rubber sleeve over the diaphragm, hope this takes care of it temporarily, As for the adjusting the carbs part, Do I have to adjust the high speed at all? Or just clean them? what do I use the spray in the carbs? Thanks.
 
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