92 Evinrude 50hp Carbon on lower piston

[Rc3469]

Have 92 Evinrude 50 hp. Removed plugs for midyear check, lower piston shows considerably more carbon buildup than top piston. Plugs are in good condition with the same light tan color. Anyone know what causes this carbon buildup on just the one piston?

 

[boobie]

Re: 92 Evinrude 50hp Carbon on lower piston

Do a compression test on it. You may have a prob in the upper cyl.

 

[Rc3469]

Re: 92 Evinrude 50hp Carbon on lower piston

Checked both cylinders, both showed 105 psi, checked with spark gap tester, top coil showing faint spark. Bottom showed good spark. ordered new coil. Thanks for your help. Bob