Problems starting 1985 90hp engine

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gwhjr98

Seaman Apprentice
Joined
May 14, 2004
Messages
36
Trying to resolve a problem with a 1985 merc 6 cyl.. 90hp engine. Hard time starting engine. I replaced the fuel line, fuel pump and cleaned the carbs. I can get it to start if I cover the carb with my hand to reduce the air intake. I assume its a vaccum leak somewhere else? It will run when warmed up for the most part so I am not sure why if its a vaccum leak it would also run poorly after warmed up. Any help or other possible places to look.
 
79Merc80

79Merc80

Senior Chief Petty Officer
Joined
Nov 22, 2007
Messages
673
Re: Problems starting 1985 90hp engine

Which carb are you covering as that engine has 3??
 
79Merc80

79Merc80

Senior Chief Petty Officer
Joined
Nov 22, 2007
Messages
673
Re: Problems starting 1985 90hp engine

After 83 Mercury did away with the choke and replaced it with the enriching system. Have to tried to push the key in as you crank the engine? Also, advancing the throttle??

Others with more knowledge will shime in soon.
 
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gwhjr98

Seaman Apprentice
Joined
May 14, 2004
Messages
36
Re: Problems starting 1985 90hp engine

Ok. got by the starting problems. I am finding that the tilt of the engine is causing or helping it run. Once I get it running.. it runs good until I trim the motor out of the water some for shallow depth. Once I trim it the engine dies out runs ok when its down. Any ideas on that? Same with starting.. if its trimmed it starts hard. Thanks.. for any help.
 
U

ufm82

Master Chief Petty Officer
Joined
Jul 29, 2003
Messages
827
Re: Problems starting 1985 90hp engine

Sounds like a float issue then if the attitude of the engine causes issues. When you cleaned the carbs did you disassemble them completely and check/reset/replace the guts? If you did all that, are you certain you have the floats set correctly? Sounds like the fuel levels in the bowls.
 
7

76canaventure

Seaman Apprentice
Joined
Mar 27, 2009
Messages
32
Re: Problems starting 1985 90hp engine

Just tossing it out there, but you may be raising the motor high enough to cause the mercury switch to kill it. Or perhaps the switch is mounted incorrectly? Disconnect it temporarily and see if that helps.
Regards,
 
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