# 70hp johnson dies at idle speed



## 1morecast (Jun 13, 2007)

my 1994 johnson dies at idle speed, runs great other then that....
what a pain in the butt trying to dock your boat when it shuts off every single time it's put into idle.
i saw a past post for cleaning out the carbs, and setting the idle screw, any idea what setting that should be at? can i just spray carb cleaner or do a kit rebuild? i did bye a new bulb and gas line and plan on putting that on....but i'm guessing that if it was a air leak it would have problems running wide open also, true?


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## EyeCatchEm (Jan 6, 2014)

It's most likely your low speed jet, try a high concentration sea foam treatment. 1 can sea foam to 1 gallon gas+your normal oil. It may fix it. I believe your idle screw should start off at 1.5-2 turns out.


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## bountyhunter (Apr 28, 2004)

carbs get a gunk build up ,do the sea foam, start motor run then let sit about three hours ,rebeat couple times, when you start the motor after siting with sea foam you,ll see a cloud of smoke ,IF IT was running good?? don,t change any adj.


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## 1morecast (Jun 13, 2007)

it was running good last year, then i had an electrical problem that took a while to fix, so it basically say for a whole year before running again...i did treat it with stable for that time.....if the low speed jet is sticky will running the Seafood through it clean it up or will i need to manually clean it? 
guess i'll try the seafoam as i have an extra tank and hook up.


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## EyeCatchEm (Jan 6, 2014)

Sea foam can fix it if done properly. As stated, run it for a few minutes then let it sit a while and run it again. You will know if it's done properly by the black smoke cloud


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## 1morecast (Jun 13, 2007)

i see dang Auto spelling had me running seafood through my tank. most likely a no-no:0
will give it a try, thanks.


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## bountyhunter (Apr 28, 2004)

I,VE never tried SEA FOOD ,but who knows.LOL SEA FOAM ,pretty good stuff . I put a bottle or two in my tank each year.


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## sherman51 (Apr 12, 2011)

im having the same problem with my 115 mercury after letting it set for 3 yrs. now im running seafoam through it. it is doing better but still has a ways to go. at least mine will idle out of the water now but still runs rough when under a load. but runs great at faster speeds.
sherman


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## 1morecast (Jun 13, 2007)

when i have time i will give it a try at the higher concentration and let you know the outcome. leaving for vacation and don't see myself getting it done for a week or so.


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## humpty dumpty (Nov 30, 2013)

1morecast said:


> when i have time i will give it a try at the higher concentration and let you know the outcome. leaving for vacation and don't see myself getting it done for a week or so.


As stated before it is probably your low speed jet,,, If it is really plugged you may have to pull carbs and clean them,,, It is not a tough job,, just pay attention how they come apart,,, take a video as you do it and you will have no trouble. count turns in on idle adjustment and make sure you return to that setting. The ethanol in today's fuel is hard on motors and if it is not treated with stable it plugs up tiny holes in the jets in short order. Also spraying cleaner into the throat of carb just runs straight through carb The cleaner has to go through the fuel line into the float bowl through the jets and then into the carb throat to complete fuel path. Good luck,,, hope this helped.


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## bountyhunter (Apr 28, 2004)

humpty dumpty said:


> As stated before it is probably your low speed jet,,, If it is really plugged you may have to pull carbs and clean them,,, It is not a tough job,, just pay attention how they come apart,,, take a video as you do it and you will have no trouble. count turns in on idle adjustment and make sure you return to that setting. The ethanol in today's fuel is hard on motors and if it is not treated with stable it plugs up tiny holes in the jets in short order. Also spraying cleaner into the throat of carb just runs straight through carb The cleaner has to go through the fuel line into the float bowl through the jets and then into the carb throat to complete fuel path. Good luck,,, hope this helped.


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## bountyhunter (Apr 28, 2004)

put the sea foam in now,that way it can realy work on the gunk.it,ll be working while your on the beach.


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## crestliner TS (Jun 8, 2012)

watch a video on you tube about using the seafoam first, lotsa important stuff. I dont think they have any videos on seafood additives though.


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## wrmdunker (Apr 11, 2012)

When it starts to die, try pumping the primer bulb. That could signal an air leak or a bad fuel pump. Seafoam may work if run thru the tank. As stated above spraying in the throat just blows right to the cylinder. If you get black smoke after a soak, that just means your cylinders had carbon build-up and needed to be de-carbed. Staibil is a good idea but not for off-season storage. Carbs should really be drained and excess tank fuel used elsewhere. Carb rebuilding is easy but you should do all 3. Get the kits and remove all the core plugs to get at the small orifices.
I have a 70Hp Evinrude........


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