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  1. #1

    Default Adjusting carbs on 60 hp johnson

    I have a 1970 Johnson 60 hp outboard. I need to know the proper procedure for adjusting the carbs. I ran it with muffs on. I have the low speed adjusted to 1 turn out. The engine still not idling as good as I'd like. I have 160-170
    compression in all cylinders. Thanks

  2. #2
    Supreme Mariner Joe Reeves's Avatar
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    Default Re: Adjusting carbs on 60 hp johnson

    (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.

  3. #3
    Supreme Mariner
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    Default Re: Adjusting carbs on 60 hp johnson

    What Joe said is good. I might add that you can't get the adjustment "right" while running on muffs. And even if it is right, it will sound rough. That's just the way they are. Get it as good as you can then fine adjust with the boat in the water and warmed up. You will have to adjust the idle speed too (RPM).

    Before you even waste your time, make sure the throttle butterflies start to open at exactly the same time and the sync is right on the money. There is more to it than just adjusting carburetors.

  4. #4

    Default Re: Adjusting carbs on 60 hp johnson

    Thanks for your replies. This info is good. I'll put it in the water tomorrow and do the adjustments. I live by Lake Michigan and the water temp is only in the
    high thirties. I think I'll use a barrel of water. I'll let you know how it turns out.
    One other question. Where does the water discharge from the engine. It seems like it comes out by the prop, all the time. I'm an old automotive mechanic and am familiar with t-stats opening and closing maintaining a minimum engine temp. Should OMC t-stat do the same?

    Thanks again, Jumpin Jupiter

  5. #5
    Honorary Moderator Emeritus tashasdaddy's Avatar
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    Default Re: Adjusting carbs on 60 hp johnson

    you can't get it 100% accurate in a barrel. majority comes thru the prop with exhaust, and then the exhaust relief port on the back of the leg, should get drops and mist.
    FLORIDA GATORS
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  6. #6

    Default Re: Adjusting carbs on 60 hp johnson

    Hi Joe, I filled a barrel of water and tried adjusting the carbs. Starting with 1 1/2 turns out, the center carb seems to be the only one responding to adjustment the way you described. I end up with about 3/4 turn out from seat on that one. The other 2 carb S/S screws can be turned all the way in and don't seem to make a difference. I pulled them
    out to inspect. They look like brand new (I rebuilt carbs abot 8 yrs ago).
    I sprayed carb cleaner into the seats and blew out with air. Didn't seem to make a difference. The engine is smoking and a lot of oil is floating in the barrel (running rich). I tried new spark plugs thinking
    I had fowled them. No change.
    I bought this boat about 1990, it looked like a brand new rig. It still does, because, it hardly ever runs.
    I'd appreciate your expertise and help.

    Thanks, Jumpin Jupiter

  7. #7

    Default Re: Adjusting carbs on 60 hp johnson

    I have a 1991 Johnson Outboard, would the adjustments be the same for it..
    When I run it at one speed setting, the RPM increases, then decreases, back and forth.... could this be due to carb. not set properly?

    thanks, Kelvin

  8. #8

    Default Re: Adjusting carbs on 60 hp johnson

    I have a 1991 Johnson Outboard, would the adjustments be the same for it..
    When I run it at one speed setting, the RPM increases, then decreases, back and forth.... could this be due to carb. not set properly?

    thanks, Kelvin

  9. #9

    Default Re: Adjusting carbs on 60 hp johnson

    I have a 1991 Johnson Outboard, would the adjustments be the same for it..
    When I run it at one speed setting, the RPM increases, then decreases, back and forth.... could this be due to carb. not set properly?

    thanks, Kelvin

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