235 78 johnson timing problem

jy118lfd

Chief Petty Officer
Joined
Jun 18, 2004
Messages
497
I have a 78 235 tl johnason that runs rough and misfires at an idle and to about 1/8 throttle. I tried to sync the carbs and ing. But heres my problem. When I do the throttle pickup setting I get 5 degrees btdc, when I advance the throttle to do total as soon as I get to the point that the motor clears up the numbers disappear and I cant read the advance. I have an advance light and no matter how much I adjust it I cant not get a timing reading. When the moter comes down in rpm the timing marks come back and it runs rough and misses again. I have taken it out and it runs great with full power and rpm except at low throttle. I need help!!!
 

clanton

Rear Admiral
Joined
Jul 9, 2001
Messages
4,876
Re: 235 78 johnson timing problem

Use a timing light without the advance,
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: 235 78 johnson timing problem

Just ignore the pick-up timing and set the full advance timing, adjust idle speed with the idle speed adjustment screw and then see how it runs.<br /><br />c/6<br />Hooty
 
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