1958 10 horse Johnson carb rebuild

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This topic contains 12 replies, has 5 voices, and was last updated by Avatar cron78 3 months, 1 week ago.

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    cron78
    US Member - 1 Year
    Replies: 33
    Topics: 25
    #175344

    I’m still struggling with the ’58 10 horse Johnson carb rebuild. Current issue is that the bushing #303947 is locked onto the low speed needle better than if it was cast in place. The needle with bushing is in the pan in the photo (if I get the pic to upload). I soaked them overnight in carb cleaner, tried PB Blaster, tried heat, and tried pure muscle and the pliers are just peeling away the outside of the bushing and needle. Seems to be a lost cause. I rebuilt a ’56 7.5 carb a couple years ago and don’t remember a bushing like this. I thought about substituting a needle from one of my donor 5.5 HPs, but they are different sizes.

    What is the bushing for? What is the correct reassembly process if/when I get new ones?

    Also, the white corrosion(?) powder I mentioned in a post a couple days ago can be seen int he second photo (again, if it uploads) along with the gasket that appears to be rubber. Ever seen a rubber carb gasket? The high speed needle was locked into the carb by similar corrosion but some heat persuasion got them separated.

    Thanks for any advice.

    Dale

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    Geer Pyron
    US Member - 1 Year
    Replies: 19
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    #175352

    Dale,
    I;ve had a similar issue with a ’56 12hp Sea King. For me, the problem was that I couldn’t back the needle out of the carb body. It would just turn and turn but not back out. I found out that that bushing was threaded for the needle but just inserted into the carb body. Then the packing washers and nut held it in and still while the needle was screwed in. Maybe look inside the carb, where that needle goes and see if it is threaded for the needle (not just the packing nut) in there.
    But, I guess you asked how to get it off. I soak all my bare metal parts in laquer thinner. And am patient. Some one told me once that screw drivers that fit the screws and patience are the most important tools for rebuilding these ol’ motors.
    I just started my 6th rebuild. Its a ’54 10hp Seahorse. Similar. I’ll take a look at mine and see if it has that bushing thing.
    Geer

    JMGP

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    crosbyman
    Canada Member - 1 Year
    Replies: 1212
    Topics: 160
    #175355

    Don’t worry about the white powder stuff… a good cleaning and it is gone

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    frankr
    frankr
    US Member - 1 Year
    Replies: 4326
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    #175357

    I really don’t have any non-destructive way to suggest, other than what you’ve already tried. But to answer the other questions, the bushing is the threads for the needle–that’s all. It is used on many carbs 10hp-up. Part # is 303947 if you are forced to destroy it. $$$$ at marineengine.com. I’ll bet there are lots of them in member’s goody boxes.

    To assemble it, put the packings on the needle, followed by the bushing screwed on only a few turns. Then the packing nut slipped onto the other end. Now, using the packing nut, push the whole assembly into the carb. Tighten the packing nut just enough to keep the bushing from spinning. Now screw the needle all the way in to gentle seating, and back out 1-1/2 turns and tighten the packing nut some more. Final adjustment when running as usual.

    If you must destroy the bushing, split it off the needle. I presume the bushing is easier to find/cheaper than the needle.

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    cron78
    US Member - 1 Year
    Replies: 33
    Topics: 25
    #175366

    Yes, the white stuff cleaned out well with a wire brush on the Dremel. Thanks, Crosby.

    Frank, Thanks for the assembly order. That isn’t the order that I remember them coming out of the carb body. The guy I got the motor from had tinkered a bit with it but didn’t do much helpful other than get a new impeller in the lower unit.

    Dale

    • This reply was modified 3 months, 1 week ago by Avatar cron78.
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    cron78
    US Member - 1 Year
    Replies: 33
    Topics: 25
    #175398

    Next question…the small hole in the mating surface seen above the fuel connection on the bottom part of the carb is supposed to go through to the bottom of the carb where the #303041 small screw plug is, correct? It looks like it is a passageway. As you can see in the pic, it is slam packed with corrosion and I didn’t want to start “drilling” it out and destroy something that isn’t supposed to be a through hole. It looks like fuel has to move through this passage past the end of the high speed needle.

    Thanks for any confirmation one way or the other.

    Thanks,

    Dale

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    bobw
    bobw
    US Member - 1 Year
    Replies: 565
    Topics: 26
    #175400

    Yes, that passage should be open. You said in a previous post you cleaned the white debris by using a wire wheel on a Dremel tool. Best way to clean a carburetor, including all the fuel passages is to let it soak in some carb cleaner solution. There are various products available for this. After a good bath, blow out all the fuel passages with an aerosol carb cleaner spray, but be careful – when you spray in one hole it will come shooting out another and could fly up right into your face. I wear safety glasses when doing this.

    Bob

    1954 Johnson CD-11
    1956 Johnson RD-18
    1958 Johnson QD-19
    1959 Johnson QD-20

    • This reply was modified 3 months, 1 week ago by bobw bobw.
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    cron78
    US Member - 1 Year
    Replies: 33
    Topics: 25
    #175406

    Thanks Bob. I thought so. I soaked this thing overnight a couple days ago and still have issues. I have been using a thin wire to try to remove the corrosion enough to get spray through. Still have about a half inch to go on the side run. Bottom run of the passage is clear. I have read the others use a sonic cleaner. That might be what this carb needed.

    Dale

    bobw
    bobw
    US Member - 1 Year
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    #175408

    Ultrasonic cleaners are great but I just use a mild solution of Pinesol in a crockpot. Works good for me.

    Bob

    1954 Johnson CD-11
    1956 Johnson RD-18
    1958 Johnson QD-19
    1959 Johnson QD-20

    • This reply was modified 3 months, 1 week ago by bobw bobw.
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    Geer Pyron
    US Member - 1 Year
    Replies: 19
    Topics: 4
    #175410

    You got a late night if you’re gonna have that thing did for Quincy tomorrow!

    JMGP

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    cron78
    US Member - 1 Year
    Replies: 33
    Topics: 25
    #175437

    Geer,

    Unfortunately, the 10 horse won’t be ready for Quincy. The low speed needle/bushing issue has me held up. Maybe someone at the meet will have a needle/bushing combo that I can acquire to finish the rebuild. Other than that, the carb is ready to remount.

    Dale

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    Geer Pyron
    US Member - 1 Year
    Replies: 19
    Topics: 4
    #175488

    Dale,
    Hope it was fun.
    Sorry I missed it. Was panning on going, but the days went by too fast.
    I may have wachoo looking for.
    Remind me to look if you did’t gitchoo one at Quincy.
    Geer

    JMGP

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    cron78
    US Member - 1 Year
    Replies: 33
    Topics: 25
    #175525

    Geer,

    Steve Wood was at Quincy and he applied mild ball peen pressure a couple dozen times and the parts miraculously separated. I hadn’t thought about tapping it while spinning it and was beginning to think I was gonna have to use a hacksaw to split the bushing off to spare the needle. I’ll reassemble and see if it fires one day this week.

    Dale

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