1997 Johnson 9.9 Firing on one cylinder

Jason R

Jason R

Active member
Figured I would ask the small engine braintrust here. Engine (1997 9.9hp Johnson) ran fine the other morning, blasted out to my spot, got skunked, picked up and started heading back. Engine would bog down when I throttled up. Slowly made it back to the ramp.

Thought it might be a fuel problem. Changed plugs and put on a new fuel line with bulb. Put it in the water same thing, no power when throttling up. Got back home, checked plugs, only one cylinder is firing. Sooo, I'm thinking power pack needs to be replaced.

Any other suggestions?

Thanks
 
Ditto, Rich beat me to it. Sounds like a bad coil to me. If you have it in a barrel and can run it at night with the cowling off you might see the coil arcing.
 
On my late 80s 35 Evinrude same issue but it was broken reed valve. You have to pull carb to check
 
Could be a reed valve but let's check the easy stuff first. The easy way to check for spark is to use a timing light. I like an inductive pickup one. Compression test is at least a clue but not the test to rely on. Much easier to just check for spark with a timing light. Dropping a cylinder can only be loss of spark, compression or fuel. I love those motors, they should be still building them. Let us know what you find. BTW a broken reed will usually spit back through the carb.
 
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