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1980 Mercury 90HP OB Idle trouble

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astroglass_81

Member
"1980 Mercury 90 HP Outboard

"1980 Mercury 90 HP Outboard
Model: 1090620 90ELPTO
Serial: 7179095

I am battling an idle issue. Engine won't idle less than 1200rpm in gear & 1600 rpm in neutral. and at idle (backing off trailer, or trying to line up to drive on trailer) engine loads up and dies. Twice I have had it in the water and twice I have had to winch it on the trailer. After the first run, about an hour on the water, I stopped and adjusted the idle mixture screws on the carbs. Went in with screw til skip, out till smooth, then 1/4 turn out past smooth, on all 3 carbs. Still acts like it loads up, stalls, and floods. Any thoughts anyone? When I'm in the water, I'd really like to be fishin' instead of sweating engine trouble.
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Thanks in advance for all your help
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You have checked the 5 bleed i

You have checked the 5 bleed inserts? --- little plastic bits between cylinders ------ you remove the bypass covers to look for them. You can inspect the pistons and rings at the same time. Good trouble shooting is a must.
 
"Does this engine have the ble

"Does this engine have the bleed inserts? as far as I know this engine has not been disassembled, and to my knowledge if they are supposed to be there, I guess they are there. And if they are there, what would be wrong with them?"
 
These are tiny plastic pieces

These are tiny plastic pieces with a small hole.They tend to get pushed out of place and fall in the lake.On my rebuilds I install an 8-32 setscrew with the same size hole and ---NO MORE PROBLEM.
 
"Do you have to remove the pow

"Do you have to remove the powerhead to service the bleed inserts? I just looked in my service manual and saw them.(5 inserts- bottom cyl doesen't get one, right?) Just wondering how involved a job like this is? Boy, I'd hate to tear in this thing and inserts be fine
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Thanks for your input.
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"Simple , you remove the intak

"Simple , you remove the intake bypass covers. You then use a tooth pick to see if you can touch the piston in the cylinder below.Stick the toothpick in the hole and rotate the flywheel , get the picture?"
 
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