77 Johnson Help stuck at lake

[kospotts]

I have a 1977 75hp johnson. Idles ok and can rev up to high rpm by manually moving carb linkage, but bogs down and dies under throttle load. Had carbs rebuilt, new gas, new tanks, new fuel lines and compression checks ok and new fuel pump but still having same problem. I need a new direction to go here as I am just about to the end of my rope. Thanks in advance. KO

 

[bigbob_FTW]

Re: 77 Johnson Help stuck at lake

Start with the spark. Check for cracks in your coils. get a spark tester and make sure it will jump at least 7/16". Also, do a compression check.

 

[gejandsons]

Re: 77 Johnson Help stuck at lake

Timing advance is not working or timing is not correct

 

[kospotts]

Re: 77 Johnson Help stuck at lake

how do I check and/or adjust timing???

 

[gejandsons]

Re: 77 Johnson Help stuck at lake

Look at the linkage & make sure nothing is broken or missing . As the throtte is opened up, it should move the timing advance. Check for worn parts on the linkage that moves. To check the timing you'll have to get a timing light.