2005 50hp 2 strke johnson backfires

[scotttt61]

Hi !
Just bought this Johnson and it's backfiring at idle and no top end,
cleaned carbs and made sure it's not the fuel filter or fuel tank.
seems like it gets alittle worse as it warms up.
Checked plugs and compression which is good
seems like it might be electrical ,maybe a coil ?

[Joe Reeves]

If the backfire you speak of sounds like a shotgun going off... yes, that's a backfire.

But if what you're calling a backfire actually sounds like a ever so mild blip, a sudden hesitation, like something spitting back out of the carburetor.... that's caused by a lean running carburetor.

Have the carburetor face plate off and while that problem is taking place, stick a couple fingers into the carburetor throat, acting as a manual choke. When the engine smooths out, you've found the offending carburetor. Yes, I know you said that you've cleaned them, however it's quite easy to overlook something within one of them.