What am I missing? (carb linkage)

[sikz3]

Ok, if I set the linkage up when engine is cold and choke is closed the engine idle stop screw rests on the fast idle cam, but once engine is warmed and choke plate opens then the stop is held off the fast idle cam because the throttle cable is in same position. Does anyone get what I am saying? Do I need to adjust the linkage to proper length with the choke open?

 

[Gary H NC]

Re: What am I missing? (carb linkage)

If you are setting the cable and idle stop it should be done with the choke open i believe.One of the pros should chime in on this..

 

[rodbolt]

Re: What am I missing? (carb linkage)

if you have a fast idle cam you have the wrong carb,
marine engines dont use fast idle as thats controled by the operator.
unlike automotive, carbed marine engines actually require operator input to work correctly.
on marine carbs the fast idle step is not on the cam, wont matter if the choke is open or closed when you set the cable adjustment.
but it would help us help you if you post what carb we are dealing with

 

[JustJason]

Re: What am I missing? (carb linkage)

It be best if you let us know what engine/carb you are working on. Pictures are also worth 1000 words....

Rodbolt.... I cant speak for every carb ever made but my rottenchester 2GC has a fast idle cam. In order to start it you have to pump the shifter twice (in neutral) then hold it just open enough to keep the idle speed screw off the cam, or else the choke wont open.

 

[sikz3]

Re: What am I missing? (carb linkage)

it is a rochester 2bbl (the original was a 17059053 but the new carb I recieved has a automotive part number although it was rebuilt as a marine carb and is identical)
Capt Jason, I assume when your choke is open the stop screw sits on the cam correct? When the choke closes how does your shifter return to nuetral if our fast idle cam prevents the cable from returning all the way back. Does it have enough give? (the cable)

 

[Don S]

Re: What am I missing? (carb linkage)

Rodbolt.... I cant speak for every carb ever made but my rottenchester 2GC has a fast idle cam. In order to start it you have to pump the shifter twice (in neutral) then hold it just open enough to keep the idle speed screw off the cam, or else the choke wont open.

They have what is still called a fast idle cam, but if you look at it, it's the same diameter over it's range. The fast idle cams on cars had steps in them that would hold the throttle higher. The marine version is smooth and the same diameter. So no speed increase while the choke is closed.

Sikz3. Need to know what year, make, model OMC, Volvo, Mercruiser etc. engine you have. No what carb.

 

[sikz3]

Re: What am I missing? (carb linkage)

1980 OMC 140hp 400 stringer.

 

[sikz3]

Re: What am I missing? (carb linkage)

Mine is smooth but I am almost certain there is a change in diameter because when I hooked the linkage up when the choke was closed it touched but once choke opened it did not contact the cam.

 

[Don S]

Re: What am I missing? (carb linkage)

You can follow the links below to your carb,
http://epc.brp.com/login.aspx?ReturnUrl=/default.aspx?brands=ej&lang=E&brands=ej&lang=E

 

[sikz3]

Re: What am I missing? (carb linkage)

What I meant by "what am I missing?" is I don't understand how to adjust the linkage choke open or closed. Thanks for the link but I do not think I need anymore parts.

 

[Don S]

Re: What am I missing? (carb linkage)

On a COLD engine. Open the throttle just a little to move the idle screw off the fast idle cam so it's free to move.
Then loosen te 3 clamping screws on the choke coil housing clamp. Turn the choke coil in the direction that allows you to keep the choke open. Now turn the coil so the choke JUST closes. Tighten the screws.
This works perfect for me. Not too tight and not too loose.