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Enrichment knob on 1985 25 HP Mercury on a WMC carb

It holds something open so that extra fuel goes into the engine-----------------It is used instead of a choke butterfly and both do the same thing. -------The enrichment just works a little better and faster, which means quicker starts.
 
I use it just as if it were a choke. Recently I took the carb off to inspect the bleed hoses (ends input in front of the reeds.) After reinstalling the carb the motor dies when the enrichment knob is pushed back in. If I move the knob back just a little into its 1st detent, which creates a little pressure on the plunger diaphramg motor runs. It should run nromally with knob pushed back in. Can't figure this out.
 
That's how those carbs work. WHen the motor is warmed up enough to go into gear without stalling, you push the "choke" all the way in. It's really a great setup.

Jeff
 
fastjeff said:
That's how those carbs work. WHen the motor is warmed up enough to go into gear without stalling, you push the "choke" all the way in. It's really a great setup.

Jeff
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Any idea though why I have to have knob slightly out to prevent it from dying? Prior to my removal of the carb and reinstalling it was working as you describe. It's almost like it burns what fuel is in the bowl and then dies (when knob all the way in.)
 
I think the fuel is obstructed from the carb bowl and slight pressure on the pump diaphragm gives an opening for fuel to be injected into the reeds and crankcase.
 
There's a thin rod that pulls on the spark advance to raise the idle speed when the choke is on. If that rod is not adjusted properly the motor will not idle fast enough to stay running. Try adding a bit of cold idle speed with it--just be sure it's not adding speed with the choke all the way in.

Jeff
 
fastjeff said:
There's a thin rod that pulls on the spark advance to raise the idle speed when the choke is on. If that rod is not adjusted properly the motor will not idle fast enough to stay running. Try adding a bit of cold idle speed with it--just be sure it's not adding speed with the choke all the way in.
*
Jeff
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Thanks.* Re: Pn my 09-27-2010 12:49 PM post I had the idle screw turned all the way in.* Doh! It could only get fuel via the enrichment assembly.* Fixed this.
*
*The thin rod you mention is called an "idle wire,"*but I too like to think of it as a thin rod.* *The end opposite the spark advance is attached to the "fast idle, ratched lever assembly," which is part of the enrichment knob assembly.* I have the instructions on how and when it is set to adjust the RPMs.*
*
Here's my problem.* When I removed the carb the thin rod became totally detached and I failed to mentally photo where and how it was attached to the spark advance under the flywheel.* (1) Does it attach by hooking on to the back of*spark advance*lever, or (2) does it attach/hook up into the lever?** (1) seems logical, but the ratched lever is stretched beyond the ratchit limit, i.e., it is open and no longer a ratchit.
*
Anybody with a Merc 25XD can see what I am trying to describe.
 
Ive got one but its hard to describe how to reattach,except to say,put the rod into the lever on the carb first,just hook in by two right angle bends,then guide the rod thru the small slot in the base plate ,then you can fit the carbie onto the studs that hold it.I tried fitting the rod to the carbie in place,very difficult.then,when you twist the choke knob,it pulls the lever forward onto the enrichment valve,as well as advancing the spark.Hope you can follow all that.By the way,if any body has one of those enrichment valves for sale,Ill buy it.I need one for my outboard carbie
 
budgie14 said:
Ive got one but its hard to describe how to reattach,except to say,put the rod into the lever on the carb first,just hook in by two right angle bends,then guide the rod thru the small slot in the base plate ,then you can fit the carbie onto the studs that hold it.I tried fitting the rod to the carbie in place,very difficult.then,when you twist the choke knob,it pulls the lever forward onto the enrichment valve,as well as advancing the spark.Hope you can follow all that.By the way,if any body has one of those enrichment valves for sale,Ill buy it.I need one for my outboard carbie
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I'm just asking about the location of the idle wire under the flywheel andattached to the timing advance. See my attachment and is it (1) or (2)? btw I have just recently ordered parts from http://www.marinepartsplus.com/catalog/mercury/serial/25XD/+13286 reasonable and excellent shipping charges.
 

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  • 25HP Idle wire.jpg
    25HP Idle wire.jpg
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Its no 2,as when the chokes off,and when you open the throttle,the base plate swivels,so the slot travels up the wire,leaving the wire in place.if it was no1,it would try to force the wire forward,bending it.
 
budgie14 said:
Its no 2,as when the chokes off,and when you open the throttle,the base plate swivels,so the slot travels up the wire,leaving the wire in place.if it was no1,it would try to force the wire forward,bending it.
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Thanks.

All of my woes began after I had to replace the plunger element in the integral fuel pump, and I should have taken a photo of carb, throttle links, idel wire, etc. to have a before and after. A real Mercury mechanic told me once as I was going to show him a problem I was having with a 115 HP inline 6 cy. by removing something he said, "Watch out, if you don't know what you are doing you will f#* something up!" I broke the fast idle lever assembly, which I had to order and the about 1/4" off the end of the fast idle wire.
 
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