johnson v4 carbs

delsol

Senior Chief Petty Officer
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May 27, 2002
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whats under those core plugs in carbs and how do you service them....could mime be real gummed under them because i cleaned carbs but did nothing with them... i have good comp.. bad starting and interminet power then no power at all . then i spray gas in carb then in a couple of minutes it gos normal for a few minutes then barly moves i strongly think carbs...last time i had same problem i sent it to shop and they fixed it it was carbs<br />thanks bob sorry about spelling
 

Joe Reeves

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Feb 24, 2002
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Re: johnson v4 carbs

Bobby.... It would help if we knew exactly what make engine, year, and hp you were speaking of.<br /><br />However, the description of your problem indicates that you are overlooking the fixed high and slow speed brass jets in those carburetors. You can soak the carbs forever, but if you don't clean those jets manually, the fuel will not flow through them properly.
 

delsol

Senior Chief Petty Officer
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May 27, 2002
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Re: johnson v4 carbs

76 135 hp johnson i was trying to find out how to remove the core plugs joe and how do i replace them is it a special tool because i cleaned and soaked them a lot but did not extract the core plugs i think thats my problem
 

Joe Reeves

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Re: johnson v4 carbs

Hit the core plug with a center punch in the center slightly so as to cave it in somewhat, then gently tap in a pointed scribe to pry them out. Be careful not to insert the scribe too far as that would damage the interior portion of the carburetor. The new core plugs are dome shaped so that they fit loose. Tapping that dome with a small hammer installs them tightly.
 

Solittle

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Apr 28, 2002
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Re: johnson v4 carbs

When you get the old plug out use high pressure air to blow out the crud that gets in the inner passages that you can't see.
 

delsol

Senior Chief Petty Officer
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May 27, 2002
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Re: johnson v4 carbs

do you think with poor running with good commpression that those jets can be cloged under core plugs......i think i will remove carbs and do what you said next weekend
 

Hooty

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Oct 2, 2001
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Re: johnson v4 carbs

I've never removed a core plug in my life. Shouldn't be necessary. <br /><br />c/6<br /><br />Hooty
 

delsol

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May 27, 2002
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749
Re: johnson v4 carbs

hooty are there jets inside the core like joe reeves said or am i wasting my time...i wont start unless i prime it with gas and in water it idles then wont go fast sometimes it will and then stall if i spray gas in carbs it will take off after a long delay the run slow again the boat wont stick me it always hobbles back to dock ....when i brought carb kits i soaked and cleaned all visible parts the carbs were very clean...when i had promblem a few years ago the dealer did carbs and told me not to ever take them apart again ,,,i have 3 years tech schooling on auto and over 10+ on cars but dont know **** about boat carbs<br />thanks
 

Joe Reeves

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Feb 24, 2002
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Re: johnson v4 carbs

Bobby..... I never said that there were jets under those core plugs. The high speed jets are located at the center bottom portion of the float chamber. Re-read my original reply.<br /><br />My second reply pertained to your answer to me whereas you were certain that the problem existed with the passageways under the core plugs, and you insinuated that my first reply was of no value to you.
 

delsol

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May 27, 2002
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Re: johnson v4 carbs

thanks joe reeves i misunderstood you joe i am sorry
 

carmangary1

Seaman
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May 11, 2003
Messages
52
Re: johnson v4 carbs

I removed mine the other day. The official Johnson service manual said to remove them you use a 1/8" drill bit to drill through them and not to exceed 1/16" when you drill through. I recommend using a drill press for fine control of depth. You use a punch to pry them out once you have a hole.<br /><br />There is nothing under the core plug except for a hole that lets you get to the little fuel holes that squirt out into the throats of the carbs. You can think of them as manhole covers I guess.<br /><br />On my carb, the fuel flows through the jets (I think it is the low speed jets) then it goes under that core plugs and out the throat of the carb.<br /><br />To install the plugs, you are supposed to put a small bead of OMC sealant 1000 around the edge of the core plug and then lay them in the hole concave side up. You then flatten them out to expand them so that they seal the hole.<br /><br />I don't know what OMC sealant 1000 is so I didn't use sealant at all. It looked like the ones I took out didn't have any on them either. Does anyone know what OMC sealant 1000 is?<br /><br />Gary
 

jim dozier

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Jan 8, 2003
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Re: johnson v4 carbs

Shouldn't that be convex (high side) out, not concave.<br />Also, Joe could you expand on "clean those jets manually"?
 

carmangary1

Seaman
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May 11, 2003
Messages
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Re: johnson v4 carbs

You are right. Convex side out. I am interested in how to manually clean the jets, also.
 

G DANE

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Nov 24, 2001
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2,476
Re: johnson v4 carbs

The iddle and intermediate jets can be cleaned manually, by carefully running a thin wire through them, i.e. one core from a steel wire brush, held in a plier. This should be done very carefully, in order not to damage jet. Blow compressed air through them, from carb bore and out.
 

jim dozier

Lieutenant Commander
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Jan 8, 2003
Messages
1,970
Re: johnson v4 carbs

Would something like monofilament fishing line be safer?
 
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