5.5 wont idle in gear low speed

oneribshyguy

Cadet
Joined
May 2, 2014
Messages
8
First timer here... I have a 57 Johnson 5.5 seahorse compression is 70lbs each cyl took carb off and cleaned... needles hi n low looked great. new gas, she runs fine hi speed (adjust hi speed first) screwed low speed al the way in backed off 3/4. But as soon as I put it in gear and try to adjust low speed it eventually dies no matter where its adjusted... I go one way in small increments n then the other until she stumbles... Is it maybe points or timing NEVER PLAYED WITH THAT STUFF. Id probably really mess that up.... HELP!
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 5.5 wont idle in gear low speed

You arn't trying to idle the engine to slowly are you?
You might want to check the spark, make sure it will jump a 1/4" air gap and is bright blue.
What plugs are you using, are they gapped properly?
 

ddwilson

Petty Officer 2nd Class
Joined
Apr 8, 2012
Messages
116
Re: 5.5 wont idle in gear low speed

Try readjusting high speed should start at about 3/4 but low speed should start at about 1 1/2 and adjust in @ 1/8 increments from there.
 

OptsyEagle

Lieutenant
Joined
Sep 13, 2006
Messages
1,365
Re: 5.5 wont idle in gear low speed

another check is to verify that your timing advance is set correctly. As you turn the throttle grip you will notice that a throttle cam comes around and pushes on the carburetor's throttle roller. There should be a line or mark on that throttle cam. When the throttle cam JUST touches the carb's roller, that mark should be in the middle of that roller. If it is not, there should be a couple of screws on the starboard side of the cam that can be loosened to adjust the throttle cam.

Make sure the choke is NOT engaged when you are doing this link and sync. adjustment.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: 5.5 wont idle in gear low speed

You are gonna have to pop that flywheel off to have a look at those original cracked coils ;)
 
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