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9.9 won't low idle

K

Ksoup

New member
99 Johnson stopped idling properly last season, water was coming out hot and high temp alarm was sounding off. Installed new impeller kit, carb was cleaned thoroughly twice and inspected fuel pump. Idle screw was reset properly aswell. Also swapped fuel lines to no avail. Anybody run into the same kind of issue?
 
racerone said:
A 4 stroke or 2 stroke ?----Model # is ?-----Post the results of a compression test , the actual values.
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Agreed. Your title says 9.9 but then you talk about a 99 Johnson. Please post your model number so we know exactly which outboard is the issue.
 
A 2 stroke.----Post the actual compression values here.-----That is always the first step in trouble shooting for me.----Some will argue with the concept.
 
Agreed, post compression #'s. If you had a hot alarm and you've set everything properly on the carb and you still have running issues, it's possible you've warped the head or have a bad head gasket. Worst case you've scored one or both cylinders.

On a side note, the old 9.9's were notorious for the upper water tube grommet to deform and cause a water flow restriction. It's #17 and #19 on this part diagram --> 9.9 Exhaust Housing Diagram. It is Part # 330426.

I'm not certain your 1999 model had this exact problem, but I know this was relatively common on the 80's models and older.

KJ
 
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