Anyone know about carbs?

Banditz

Petty Officer 2nd Class
Joined
Apr 21, 2010
Messages
168
I have a 165merc. 470 is what most of you guys call it. Four banger...anyway I rebuilt the carb last night and the only thing I have left to do is figure out where to install the piece that the wire plugs into. Sorry no pics, but what it does is holds the butterfly open, almost like a automatic choke, or idle control. The top butterfly in the carb is what I am talking about. The part has a male end that accepts a wire from the boat. Also has a ground hook up...it is bolted to the side of the two barrel carb. The other side of the carb has a linkage that is mech. controlled. When you open the gas all the way the top butterfly will open. I am guessing the object controlls the idle. I took it off and cleaned inside it and there was a coil of wire..that kinda catches a hook that controls the butterfly.


I know is is kinda gonna be a long shot, but I have typed this whole thing off my black berry! Internet is down at the moment and therefore I cant take a pic and add it here. Thanks for doing what you can. I am trying to find out how to set the part. Three screws hold it tight, but it rotates around and around and I just cant seem to get it right.
 

superbenk

Commander
Joined
Oct 27, 2008
Messages
2,033
Re: Anyone know about carbs?

What you're describing is indeed the choke. You appear to have an electric one. Sometimes they are vacuum/temperature operated.

When I rebuilt my carb, the directions instructed me to adjust the choke butterfly so that it was fully closed with a 1/16" gab (I'm remembering off the top of my head, might have been 1/32" - hopefully someone else can chime in with an accurate number). When the engine warms up, the choke should stay open.
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Anyone know about carbs?

from s/m #3 for a mercarb 2bbl.
choke unloader. w/ throttle plates completely open. gently press down on choke plate. there should be a .080'' opening between the choke plate and the air horn assy.

normal choke setting is such that scribed mark on cover is in line with the long case mark on choke housing.

ya should get yourself a mercruiser service manual if your working on your boat. it has all the facts in it...
 

Banditz

Petty Officer 2nd Class
Joined
Apr 21, 2010
Messages
168
Re: Anyone know about carbs?

Thanks alot guys! I found out today what it really was. My only thing is now, I have been told it is supposed to be fully open, and now on here that is is supposed to be barely open...LOL. I am guessing the guys on here are right, not just because of the use of a manual, but because you guys know what I am dealing with. BUT can anyone else confirm, or at least agree that it should be as posted prior to my post? Thanks..

Yeah, I really need a manual! That is for sure! I just keep missing them on ebay!
 

superbenk

Commander
Joined
Oct 27, 2008
Messages
2,033
Re: Anyone know about carbs?

As stated before, the choke butterfly will be in the closed position when the engine is cold so the mixture is rich (less air flow). When the engine warms up to operating temps, the butterfly should be fully open (leaner - more air flow). You adjust the closed position so there is a gap to allow some air flow (fuel needs oxygen mixed in to be combustable), not sealed tight.
 

bigdan1

Petty Officer 3rd Class
Joined
Aug 9, 2010
Messages
95
Re: Anyone know about carbs?

when choke is cold , the top butterfly should be completetly closed when throttle is moved partially ,unless you put the thottle to wot position , then the mecanism should open the butterfly by around .060-.080 to give it more air !
 

Banditz

Petty Officer 2nd Class
Joined
Apr 21, 2010
Messages
168
Re: Anyone know about carbs?

Ok guys, thanks ! Got her purring like a kitten now! Hopefully sat. when i take her out I will have more power. She does 47 now, but hopefully after me cleaning the carb out of all kinds of junk, she will do a little better. Who knows, may hit 50!
 
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