1982 Johnson 7.5hp Backfires but No Start (Wrong Carb?)

[racerone]

Remove low speed mixture needle.----Post picture of the tip.----Some have been known to be molested.-----The screw sticks out too far of the cowling as well.

 

[OptsyEagle]

You said, after switching the plug wires, that she started right up and ran for about 2 minutes and died and you could not restart it. Have you tried restarting it since? When a motor is about to die like that it is a good policy to squeeze the primer bulb again to see if the motor revives temporarily. This allows you to diagnose the problem to a fuel pumping problem. Arguably you have already diagnosed it to a fuel problem, since it ran for a while and then died. If you squeeze the bulb again and still cannot start it then it may not be a fuel problem.

 

[Michawilden]

Definitively a wrong carb on this engine. Cam roller is from another style (modern) carburetor than this one. I believe the older 6 hp has a smaller roller. But definitively not the correct carb. Maybe you can get it to run on this carb? there might be a difference in main jet and bore between a 6 hp and 7.5. I would do a compression reading, if that turns out oke try to find the correct carb for the motor. You might never get it to run correctly simply because it is the wrong carb.