If it runs " great " , then why do you feel you need to adjust stuff.----Best to replace water pump impeller.----Test overheat horn.----Post compression test numbers and record them for future reference.
According to the parts book the primer valve appeared in 1983 on the 70 HP.----Something is unique to your motor.---Wrong ID plate or powerhead was replaced.
Does spark jump a gap of 3/8" ( 1 cm ) on all leads ?----The type of sparkplug has nothing to do with that test.----Might be running on 3 of 4 cylinders.----Clean carburetors.-----Remove lower unit and check for carbon blocking the exhaust.
The 79 models did not come with the primer from factory.----But lots of work / replacement of powerhead perhaps.-----First used on the 70 HP model in 83 I believe.
??----Super high RPM- ?-----Could be an issue in the lower unit.-----High RPM may have done damage to valve train.----Sheared flywheel key.-----Time to do some inspection.
Information needed.-----Post compression numbers.--Does throttle plate open all the way ?-------Have you checked flywheel key ?----Does spark jump a gap of 3/8" or more on oth leads, yes or no ?----Sounds like it is running on 1 cylinder.
I do not believe the 85 model used the stuffers.----I believe this will bolt together fine as it is.----If you are worried then take a razor blade or exacto knife and trim them to your liking.
This motor needs more work than what the owner is aware of at this time.-----In some areas there are better motors than that thrown out for scrap.----Sorry to be blunt here.
Quick silver is MERCURY !----Know of a dealer that offered a " winterizing special " package one season.-----Installed aftermarket impellers.-----Had to send his people out to pull 28' boat out of the water to install new impellers.-----No more trying to save folks $10 after that episode.
Be careful with gasket sealer on outboards.-----I have seen a EWE TOOBER smear lots on gaskets.-----I am sure he did not realize he was possibly blocking oil recirc channels !!
