Johnson Sea Horse 10

KidMuddy

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Jul 22, 2004
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9
Hi, <br /><br />My FIL has an old Johnson Sea Horse 10 that is having carb problems. It won't idle, is hard to start, but runs well at high speed. The model number is QD 21 S and the serial number is 2114050 . Would anybody know what year and HP this motor is so we can find some rebuild parts for it? Thanks for any help.<br /><br />Dean
 

KidMuddy

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Jul 22, 2004
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Re: Johnson Sea Horse 10

Thanks, Petrolhead for the quick reply. The person it was bought from said it was a 1965 and it was rare since it was white in color. It looks like it was repainted though, since I see some ugly green paint coming through on the midesction. Anybody know what color these were originally? (I'm kinda new to boat motors if you couldn't tell.)<br /><br />Dean
 

BoatBuoy

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May 29, 2004
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Re: Johnson Sea Horse 10

If it is a 1960, primary color is white (actually "Warm White").
 

petrolhead

Chief Petty Officer
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Oct 16, 2003
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Re: Johnson Sea Horse 10

Are you sure that "ugly green colour" isn't the zinc chromate primer coming through the white? That's what it sounds like.
 

JB

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Mar 25, 2001
Messages
45,907
Re: Johnson Sea Horse 10

Be sure to use 24:1 fuel mix in that 1960, Muddy.<br /><br />50:1 is too lean for some of the bearings.<br /><br />Good luck. :)
 

KidMuddy

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Jul 22, 2004
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Re: Johnson Sea Horse 10

Thanks for the info guys. I'm not sure about the green color, only that it's ugly. Could be primer. And I'm using 24:1 mix, I had read in another post that 50:1 would be way too lean. <br /><br />Anyway, I got the carb sorted out, so I decided to take some laps around our pond. Well, now I need a shear pin for the prop. Oops! Anybody know what size it is? I'm still waiting on a repair manual, and the nearest Johnson dealer is 75 miles away.
 

alcan

Commander
Joined
Dec 14, 2001
Messages
2,505
Re: Johnson Sea Horse 10

Hi Kid<br />Call him up and ask him to drop some in the mail for you. Just give him your credit card # and he'll send you a new motor as well.
 

KidMuddy

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Jul 22, 2004
Messages
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Re: Johnson Sea Horse 10

Me again. I'm having a heck of time getting this thing to run properly. It'll start OK, and run decently at high speed but will not idle. It almost seems like it's kicking back, or "twitching". It's kind of hard to explain I guess. <br /><br />One of the coils was cracked and falling apart so I replaced it, along with points and condensors. The points are gapped at .020 and both plugs have good spark. But I still can't get it to idle. <br /><br />Oh yeah, the carb was rebuilt, but the low speed needle looks pretty grooved but I haven't been able to find a new/used one. No matter how I adjust the low speed needle it really doesn't seem to make a difference. I really am out of ideas on what to do next. Does anybody have any ideas?
 

Paul Moir

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Nov 5, 2002
Messages
6,847
Re: Johnson Sea Horse 10

If the idle control doesn't seem to do much, it's likely still blocked. Did you remove the soft core plugs when you rebuilt the carb and directly look at the low speed orifaces? If not, do you still have the plugs?<br />Some folks have had some success refiling the needle if it's been grooved. You can chuck it up in a drill to do it, but it'll take some talent to make it nicely tapered and still on center.<br />Also, which brand manual are you working out of?
 

KidMuddy

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Jul 22, 2004
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Re: Johnson Sea Horse 10

Hi Paul, I didn't remove the plugs when I rebuilt it. I did it last summer and was in a hurry to get on the lake with the FIL and I guess haste does make waste. The needle tip was actually bent a little, it was that way when I took it apart. I tried to straighten it as best I could but I wish I could find a new one. I've got the Seloc (sp?) manual that I've been using.
 

Paul Moir

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Re: Johnson Sea Horse 10

I figured it was the Seloc - they left out the step on the core plugs in the carb rebuild instructions. Add this to them:<br /><br />Disassembling:<br />Your new carb kit ought to come with replacement, slightly convex core plugs. Before proceeding, make sure they're they are the same size as as the ones you are about to remove. If all is well, drill a 1/8" hole in the centre of each core plug. Then insert a small screwdriver or nail through the hole, and pry the plug out. It is very important that while drilling and prying, you do not let anything damage the surfaces underneath the plug. So restrict the drill bit from piercing much more than 1/16" beyond the core plug.<br /><br />Assembling:<br />Coat the outside edge of the core plug with a slight amount of fuel proof gasket sealer. (Although this step isn't strictly necessary, I find it helps seal the plug and saves problems down the road.) Now place the plug convex side up atop the boss where the plug rests. Then, using a small drift and hammer, tap the top of the core plug so it expands until it jams tightly against the core plug's socket. Give it one extra tap for good measure.<br /><br />Chances are that the low speed circuit is still blocked and where it's most likely blocked is behind that plug. If you still have the plugs that came in the kit, you won't need a new one.
 

KidMuddy

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Jul 22, 2004
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Re: Johnson Sea Horse 10

OK, just got back from the barn and drilled out the core plug. (Luckily I'm a pack rat so I never throw anything away and still had the parts from the rebuild kit). There were four holes under the plug and 2 of them were plugged. I'll get those cleaned up tomorrow and try it out again. <br /><br />And you mentioned two plugs, where's the other one?
 

Paul Moir

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Re: Johnson Sea Horse 10

That'll do it. :) <br />Sorry, I keep saying plugs - there's only the one.
 

KidMuddy

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Jul 22, 2004
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Re: Johnson Sea Horse 10

Well, I cleaned out the passages and installed the new plug. Then I figured I would check the fuel filter again and that's when I found out that glass filter bowls and cement floors don't mix. :eek: :( <br /><br />Are replacement filter bowls avaiable or am I SOL? :confused:
 

Paul Moir

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Re: Johnson Sea Horse 10

Ah, just trundle off to the nearest outboard graveyard. If there are none nearby, get Twin City Outboards to mail you one. Although those things are NLA, they sold zillions of engines with them before '64. It doesn't have to be from a 10hp.<br />I've done that before too. I think they built those things with cement floor magnets in 'em. <br /><br />Good luck!
 

KidMuddy

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Joined
Jul 22, 2004
Messages
9
Re: Johnson Sea Horse 10

Thanks for the tip Paul. Twin CIty Outboards has these for $8 each, so I think I should get 2 just in case. :) <br /><br />And thanks for the help so far, I have a feeling that I'll get this motor going eventually.
 

KidMuddy

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Joined
Jul 22, 2004
Messages
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Re: Johnson Sea Horse 10

Well, I got the glass bowl from Twin City Outboards, and also picked up a really nice low speed needle valve to replace the old grooved and bent one.<br /><br />Got everything installed, the motor fired right up and idles nice at the "Start" position on the tiller but it won't idle any lower. The needle valve is definitely making a difference in how it idles when I turn it, but I just can't get it to idle down low no matter how far in or out it is. <br /><br />So far I've put new plugs, points, condensors, coil pack, carb kit, and low speed needle valve in. I've cleaned out the idle passages behind the core plug, mixed some fresh gas set the timing. I don't know what to do next other than just buy my FIL a new motor and toss this one. :confused: :mad:
 
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