79 70hp johnson carb question?

jjacobs007

jjacobs007

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hello all fellow boaters can anyone help me? I have a 79 70hp johnson with three carbs and my seloc manual says it only has 2 orifices.low and high.but my carbs have three i believe.just asking,anyone out there know about these carbs are have them.also posted (1979 70hp johnson no top end) but got no answers.can somebody help me want to have a good running boat this year please help!thank you .
 
tashasdaddy

tashasdaddy

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Re: 79 70hp johnson carb question?

thatis exactly why we do not recommend Seloc and Clymer manuals. you do have 3 orifice.

read carb cleaning in the TOP SECRET FILE. you just have one more jet to clean. you have low, mid and high speed jets. do not get the jets replaced in the wrong place, and mark each carb as to where it goes on the motor.

diagrams http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f
 
A

awsome66nova

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Jul 18, 2010
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Re: 79 70hp johnson carb question?

Well, I have looked at the thread and it doesn't cover the 3 carb version very well. It doesn't answer the question about fixed jets, orifices and adjustment screws. The links that someone attached to it are gone, and the ones that the guy posted pictures on are of a twin carb set up. None of which tell you how to adjust or set the link on the carbs and timing.
 
D

Daviet

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Sep 24, 2008
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8,958
Re: 79 70hp johnson carb question?

Your carbs do not have any adjustments on them, they are all fixed orifices.
A clogged high speed jet can cause a loss of power at high speed yet the engine will idle properly.
Have you checked the other systems, compression and spark, to make sure your high speed problem is a fuel problem.
What is it doing at high speed, bogging down, cutting out?
 
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awsome66nova

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Jul 18, 2010
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Re: 79 70hp johnson carb question?

I have check for blue spark, and have it, I have changed the plugs and cleaned the carbs, I put it back together last evening and took it for a spin arount the Harbor, seem like it has a little hesitation around 4700-5200. Hit the enrich button on ign. and she took off. What's up do I need to look at the fuel pump. This started about two weeks ago and prior was running like a rapedape.
 
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