johnson 28 will not idle

skeet 250

Recruit
Joined
Feb 17, 2010
Messages
1
Have An 81 Johnson 28 Hp.rebuilt The Carb Last Season And It Ran Perfectly All Year.a Friend Put An Old Tank On It With Old Gas And Thats When The Problems Started.it Will Crank But Not Idle.the Long Idle Adj Screw On The Front Of The Carb Has No Effect.took It Back Apart And Cleaned.i Did Not Take The Big Screw On The Bottom Of The Carb Out.it Looked Like A Drain.is There A Main Jet Behind This Screw Up In There?
 

psteurer

Petty Officer 1st Class
Joined
Nov 10, 2008
Messages
366
Re: johnson 28 will not idle

The big screw on the bottom would cover the high speed jet. To do a proper carburetor rebuild you really need to remove all the jets. I believe your carb also has an intermediate speed jet located at the top of the carb and then the idle speed needle valve on the side of the carb. Remove them all and clean. Your problem appears to be in the idle circuit from your description. Look into the barrel of the carburetor from the back end and see if you can see 2-3 small holes where the throttle plates meets the barrel. Get some brass or copper wire and try to poke it through and then shoot some carburetor clean through those holes. If there is crude clogging those holes, your motor will not idle.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: johnson 28 will not idle

old tank, old fuel, guarantees he contaminated the carb again. you need alcohol resistant fuel line from carb to tank.
 
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