1984 70hp evinrude upgrades

[[email protected]]

Hi people, new guy here. I'm looking to make some upgrades on my 1984 70hp evinrude.
My first question is about spark plugs. I'm getting conflicting information between my seloc online repair manual which tells me to use l77jc4 gapped at 0.040 yet the parts section suggests ql77jc4 which has a gap range between 0.028 and 0.033. Seems to me that champion suggests the QL77JC4 gapped at 0.040 would be out of product specification. Evinrude.Com says to use QL77JC4 gapped at 0.030. So which is it. I'm thinking that I'll go with the evinrude.com specs. Which leads me to wonder which other info in the manual might be questionable or out of date.

 

[racerone]

Took the plugs out of an older 25 HP MARINER the other day.-----Gap appeared to be around 0.060" or more.----That would seem to suggest it was running fine up to that point and at that gap.----Why the big concern about plug gap here ?------What is your motor doing / not doing ?----If there are problems then what trouble shooting has been done ??

 

[[email protected]]

Took the plugs out of an older 25 HP MARINER the other day.-----Gap appeared to be around 0.060" or more.----That would seem to suggest it was running fine up to that point and at that gap.----Why the big concern about plug gap here ?------What is your motor doing / not doing ?----If there are problems then what trouble shooting has been done ??

I bought the engine in pieces. have it running but I need to be flawless at low speeds. Figured I'd set it all up to spec as a starting point. No point doing all the timing and sync if I have the wrong plugs or wrong gap as this does affect performance.