no power johnson 70

toxic150

Recruit
Joined
Jul 15, 2012
Messages
1
I can idle and go at 5 mph but when I push the throttle it dose nothing just 5 mph and uses a lot of gas but no speed its a 1978 can anyone help me with this?
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Re: no power johnson 70

Welcome to iboats. You need to get a spark tester from el cheapo auto parts store for around 10 bucks and check for spark when you turn it over on all cylinders. You may have a bad coil or could be the power pack or could be fuel related. Do the spark test first and get back with us. Should be a bright blue spark and jump about a 1/2".
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: no power johnson 70

You might want to check the compression also.
 

1kruzer1

Petty Officer 2nd Class
Joined
Apr 26, 2008
Messages
110
Re: no power johnson 70

Classic symptom of a stuck timing plate. When you advance the throttle it's only spring pressure that moves the timing plate arm forward. With the engine NOT running advance the throttle control all the way forward. Now at the motor try moving the timing plate arm forward and back. You should be able to push it back and have it snap forward instantly, with no dragging or sluggishness. If you don't know which is the timing arm, look at the starboard side of the engine as you move the throttle back and forth. You'll clearly see the lower half of the arm assembly moving. The upper arm extending up from the midpoint to just below the flywheel should be moving with it, as this is the spring loaded timing plate arm.Good luck.
 
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