Lean Rich Idle Adjustment Knob

[mulv80]

I bought a 1965 Evinrude 18hp Fastwin off of ebay and have run it a few times. The motor runs great at idle and WOT. I have a question about the idle slow speed adjustment knob. The knob is set at 1. I have searched the forum for info on this knob and understand how to adjust it. I would hate to make any adjustments to a motor that already runs great. However I'm concerned that I may be running it too lean. Can anyone tell me if theres a way to tell if I'm running lean? Also if this knob is not adjusted correctly can I harm the motor. Thanks

 

[Paul Moir]

Re: Lean Rich Idle Adjustment Knob

If it sneezes or hesitates when you acellerate, your probably lean at idle. If it's lean at full throttle (carb high speed circuit), then it will sneeze there. You can also pull your sparkplugs immediatly after running the engine at full throttle (kill it at full throttle) and examine the spark plug ends. If they're bright white, you're probably running lean. You must use new plugs for this test.<br /><br />Joe reeves explains how to adjust this knob here. Since you don't have a high speed adjustment, ignore that part. The first step in this process is to disconnect the knob's linkage. When you're done, set the adjustment to whatever number you think is best. <br /><br />I think it would be hard to hurt the engine by running lean at idle, unless it is lean sneezing really hard. I've seen a crankcase sidewall blow from that once, but the sneeze was excessive.