In an earlier thread I described work (Head Gasket/Thermostat) I did on my Evinrude E8RECR trying to resolve a Plug Fouling (and running poorly) condition. In frustration I set this project aside for 6 months or so.
Taking a fresh look at the problem first I rechecked Compression--using my Innova #3612 gauge 10 pulls with opposite Spark Plug removed (engine in water tank to protect Impeller) I found 93psi Upper/ 94psi Lower Cylinder. Not bad, maybe a bit low. Could be higher with more pulls.
Moving on to check Spark-- instead of using my usual Adjustable Gap Spark Tester I used an in-line Bulb Style Spark Checker this time. I connected the Bulb Style one cylinder at a time while the engine was running, everything from Idle to Medium RPM's. Previously with the Adjustable Gap Spark Tester I tested WITHOUT engine running--I gave the Pull starter several good yanks while watching the Spark Tester (positioned at side of rear engine--difficult to see-- but not impossible-- while pulling the rope). Long story short with the Inline Bulb Tester I can clearly see (especially at Dusk under low light conditions) that the Lower Cylinder is getting a sporadic Glow particularly at lower RPM's while the Upper Cylinder glows much brighter and more continuously.
So obviously there is an Ignition problem with Lower Cylinder. Under dark conditions I inspected the engine and especially the Lower Spark Plug Lead Assembly (#6 in diagram) for arcing, etc--and saw no problem. Which leads me to conclude that the Root Cause may or may not be the Spark Plug Lead Assembly. That is, arcing would be an obvious problem. But lack of arcing does not mean the Lead Assembly is 100% good.
So to totally rule out the Lead Assembly as root cause first I would think next step is to swap the Lower and Upper Lead Assemblies--i.e. on both cylinders disconnect the Lead Assembly at the #3 Ignition Coil Assembly and reconnect to Spark Plug--then redo the Bulb Test. See if the problem follows the wire vs. stays at Lower Cylinder.
A couple questions: 1) Does the Lead Assembly simply pull straight off the Coil Assembly, or is a slight twist required? 2) If swapping the Lead Assemblies does not indicate a defective Lead Assembly then is Ignition Coil Assembly #3 the next component to Test? If so, what is the Test? 3) If #3 Coil Assembly is not defective then is Power Pack #23 the third-in-line component to Test? I hope worse case the Coil (cost= $40-55) is the problem, not Power Pack (around $100).
Thanks for any advice.
Taking a fresh look at the problem first I rechecked Compression--using my Innova #3612 gauge 10 pulls with opposite Spark Plug removed (engine in water tank to protect Impeller) I found 93psi Upper/ 94psi Lower Cylinder. Not bad, maybe a bit low. Could be higher with more pulls.
Moving on to check Spark-- instead of using my usual Adjustable Gap Spark Tester I used an in-line Bulb Style Spark Checker this time. I connected the Bulb Style one cylinder at a time while the engine was running, everything from Idle to Medium RPM's. Previously with the Adjustable Gap Spark Tester I tested WITHOUT engine running--I gave the Pull starter several good yanks while watching the Spark Tester (positioned at side of rear engine--difficult to see-- but not impossible-- while pulling the rope). Long story short with the Inline Bulb Tester I can clearly see (especially at Dusk under low light conditions) that the Lower Cylinder is getting a sporadic Glow particularly at lower RPM's while the Upper Cylinder glows much brighter and more continuously.
So obviously there is an Ignition problem with Lower Cylinder. Under dark conditions I inspected the engine and especially the Lower Spark Plug Lead Assembly (#6 in diagram) for arcing, etc--and saw no problem. Which leads me to conclude that the Root Cause may or may not be the Spark Plug Lead Assembly. That is, arcing would be an obvious problem. But lack of arcing does not mean the Lead Assembly is 100% good.
So to totally rule out the Lead Assembly as root cause first I would think next step is to swap the Lower and Upper Lead Assemblies--i.e. on both cylinders disconnect the Lead Assembly at the #3 Ignition Coil Assembly and reconnect to Spark Plug--then redo the Bulb Test. See if the problem follows the wire vs. stays at Lower Cylinder.
A couple questions: 1) Does the Lead Assembly simply pull straight off the Coil Assembly, or is a slight twist required? 2) If swapping the Lead Assemblies does not indicate a defective Lead Assembly then is Ignition Coil Assembly #3 the next component to Test? If so, what is the Test? 3) If #3 Coil Assembly is not defective then is Power Pack #23 the third-in-line component to Test? I hope worse case the Coil (cost= $40-55) is the problem, not Power Pack (around $100).
Thanks for any advice.