Am I missing something on my carb...?

Johnnieboy13

Cadet
Joined
Mar 23, 2012
Messages
6
Hello Forum...

Will try not to make this long, or a snooze fest for you......

I have a 1985 Century 18ft bowrider, love it, it has a mercruiser 140 / 3.0 i/o with an alpha one outdrive. More recently I have re timed, new plugs and wires, rotor arm and oil changes. All is good there.

My issue is the idle setting. I have attached photos of the throttle linkage set up, I do believe the reason I cannot set the tick over as I want it is because there is an adjustment screw missing.... need some advice or a photo of someone elses set up so I can get it sorted... my idle speed is either way too low or way too high, dont want to screw the out drive gears with too high, and am getting pissed with too low and shutting down when in the marina in neutral waiting to get onto a jetty !! ps, what should my tick over be set at approx? 800ish ? please help if you can, many thanks in advance....

Oh the carb info... MCM 120/140 1389-8490throttle linkage.jpg throttle linkage.jpg
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Am I missing something on my carb...?

You have a couple of things wrong. The idle set screw and spring is missing, and the idle cam and link to the choke is backwards.

Untitled1.jpg
 

Johnnieboy13

Cadet
Joined
Mar 23, 2012
Messages
6
Re: Am I missing something on my carb...?

You have a couple of things wrong. The idle set screw and spring is missing, and the idle cam and link to the choke is backwards.

View attachment 148391

Hi Don

Yep you're right, thanks for the picture, that really helped. I have put it back in correct order, looks better, will have to find out where to source an idle screw and spring.... many thanks for your help.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Am I missing something on my carb...?

Any screw with the proper thread would work. The spring is just there to put pressure on the screw so it doesn't turn by itself. A regular nut to lock it down would work.
 

Johnnieboy13

Cadet
Joined
Mar 23, 2012
Messages
6
Re: Am I missing something on my carb...?

Any screw with the proper thread would work. The spring is just there to put pressure on the screw so it doesn't turn by itself. A regular nut to lock it down would work.

Yep, will find one... again, thanks for your help.
 
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