Mercarb help please

[Chuckles88]

Just got done rebuilding a 2bl mercarb and fired it up. The fast idle screw binds up the choke plate. I’m sure it’s something silly. When I adjust the screw to where I need it as far as idle, it won’t allow the choke plate to move. Thanks

 

[Grub54891]

HHmmm.. I'm not sure on that one. Sounds like the linkage was assembled wrong. Can you get a pic of the linkages, and carb for reference?

 

[Chuckles88]

[No message]

 

[achris]

When I adjust the screw to where I need it as far as idle, it won’t allow the choke plate to move.

It's working as designed. The idle speed screw stops the cam moving when you're in the idle position. That will stop the choke plate moving. That's why you need to 'single stroke' the throttle in the morning to set the choke.

Chris.......

 

[Chuckles88]

Should the fast idle lightly touch the cam? To get my correct idle and to have it run it has to be screwed pretty hard into it.

 

[Grub54891]

Hhmm. I looked up a 2bbl carb, Linkage appears to be the same, Maby the angle of the pic, This one looks higher on the linkage. Have you tried opening the throttle a tad and see if the choke plate moves? Or is the choke spring binding it up?
Edit, I have to agree with Achris,

I thought this was the case, moving the throttle frees it up.

 

[achris]

Marine engine... No fast idle. Do you mean the 'idle speed screw'?

Disconnect the throttle cable while doing idle adjustments. When you're happy with it, adjust the cable to suit the position of the throttle lever, and refit the cable.

Chris.....

 

[achris]

 

[Chuckles88]

Yes the idle speed screw. Mikes carbs calls it fast idle. As long as the cam is supposed to bind up in neutral I believe I’m good after a cable adjust. Much thanks

 

[Chuckles88]

Not too sure why a rebuild would cause a linkage adjust but if it needs it...

 

[achris]

...Mikes carbs calls it fast idle. ...

Most of Mikes clients are for cars. And on cars, they do have a fast idle cam. 'Fast idle' on a boat would have people destroying drives in very short order!

Not too sure why a rebuild would cause a linkage adjust but if it needs it...

If the carb was dirty, the idle screw may have been in a little more to make up for the low fuel flow. You have a nice clean carb now and it'll need less of the throttle open to idle correctly. Yes, a cable adjustment is called for.. Any adjustment to the carb requires it..

Why are you making this difficult?

Chris....

 

[Chuckles88]

Haha that is precisely what my wife said. I guess I like to know why more than most. Thanks again Chris. You have answered a lot!

 

[achris]

Haha that is precisely what my wife said....

Our wives must be twins. (and I never said that!)...

Chris.....