Evinrude E115TLCNB 1982 rpm bog at neutral idle and in gear(idle speed)

[Michaelc19]

Rpm loss in idle (neutral to in gear at idle) giving it throttle to raise rpm brings it back to steady rpms but it will eventually bog back down and lose rpm until throttle is given again. Runs perfectly fine at plane.
Spark plugs, coil packs, power packs are all new
Carbs have been rebuilt
Head gaskets have been replaced
15 psi low in 1 cylinder but no wiggle on any
Stator has been tested with ohm meter
Spark has been tested at 7/16 gap bright and blue
Any ideas will be great and appreciated

 

[havoc_squad]

Rpm loss in idle (neutral to in gear at idle) giving it throttle to raise rpm brings it back to steady rpms but it will eventually bog back down and lose rpm until throttle is given again. Runs perfectly fine at plane.
Spark plugs, coil packs, power packs are all new
Carbs have been rebuilt
Head gaskets have been replaced
15 psi low in 1 cylinder but no wiggle on any
Stator has been tested with ohm meter
Spark has been tested at 7/16 gap bright and blue
Any ideas will be great and appreciated

I would be doing a leak down test on that cylinder with the biggest drop in difference. If its more than 10% difference than the rest, it needs a leakdown test.

Issues with engine compression are often revealed at idle under load. Users/owners often try to fix it with increasing the idle in neutral in the attempt to bandaid the issue.