1984 Merc Black Max, 200 Hp High Idle

[Bassgod]

I need suggestions on what could cause this 200 Merc to idle at 3700 rpm. It does this from initial start whether it is hot or cold. Engine has set for a year or so with fuel inside, so my initial suspect is that the carbs need cleaned. Possibly a float sticking.
I have checked all vacuum lines and oil lines and do not see any cracks where it could be sucking air. All 3 carbs seem fine from the outside.
Any suggestions would be appreciated, otherwise I will pull all 3 carbs of this customers boat and thoroughly clean them.
Thank you.

 

[tashasdaddy]

Re: 1984 Merc Black Max, 200 Hp High Idle

that would be my 1st step. becareful not to get a run away with that high idle. unless the timer plate is stuck.

 

[j_martin]

Re: 1984 Merc Black Max, 200 Hp High Idle

My first reaction would be to look for sticky throttle linkages, especially trigger rotation parts.

John

 

[Bassgod]

Re: 1984 Merc Black Max, 200 Hp High Idle

Thanks guys I just got the boat and I am going to get started.

 

[j_martin]

Re: 1984 Merc Black Max, 200 Hp High Idle

gummy linkages, or mouse nest.