adjust carb?

[michaeli84]

I have a 140 mercruiser 1985. It has a 2 barrel rochester carb. I have a rough idle and i am running rich. How do i adjust the mixture so i can have a smoother stronger idle? thanx mike

 

[180shabah]

Re: adjust carb?

Start with a manual - check out the DIY sticky at the top of the forum.

Verify choke opperation also.

 

[fat fanny]

Re: adjust carb?

To start w/ perfrom a complete tune up and then make sure all electrical connections are clean and making good contact.Then make sure that your timing is to spec, check all the fuel pick up tube in your tank and it's screen for debree as well as your fuel delivery tube, anti siphon valve and vent at this point is where the merc manual comes into play if you have one follow the intructions to the "T" and then tweek from there. If you don't have the Merc manual download it from the stickies section @ the top of this forum for your powerplant year and make I believe it's #13?. good luck!

 

[T-Bone Coug]

Re: adjust carb?

You may be flooding, but as all good techs do, make sure ignition system is all good. Full tuneup (points, condensor, plugs, wires, cap, rotor, and coil all must be within spec) first, then you can mess with the rochester.

If everything else is good, check choke for proper operation.

If choke is good, look to see if fuel is dripping into barrel of carb when it is idling.

If so:
a) Float is out of adjustment.
b) Float is too heavy (possibly cracked/absorbed fuel)
c) Needle valve is worn

To fix these, I recommend a complete carb rebuild.

If no drips, then adjust mixture as the Merc manual #10 says (see adults only sticky).