Mercruiser 120/140 carb question

[karhawk]

What are differences if any between the 120 and 140 merc 2 barrel carbs. They are both rochester 2gc carbs with the same rebuild kit part number. I have a good running 120 engine and a 140 engine that has been sitting, I want to swap over the carbs.

Thanks

Chris
Oakland, cA.

[elkhunter338]

I am thinking the jets mightbe different. I am not an expert between the 120 and 140, just my thought. I switched from a 1971 140hp to a new 2007 140hp and swapped the carb. The old carb ran too rich on the new engine and I had to lean the main jets out. I had a 50/51 and now I think I have a 48/50 or 48/49 it has been a year or two since I swapped jets and it runs good (maybe a touch too lean). But the 50/51 was running way too rich, plugs where sooty and soot would show on the water when I started the motor. after the outdrive sat for awhile at dock and it idled too rough no mater what I did with the idle jets.
Now it idles smooth all the way down to 700 rpms.

[bigskiohio]

i am guesing they are the same as #s are the same the 140 is just a bigger engine.

[Fishermark]

They are both rochester 2gc carbs with the same rebuild kit part number.

If they are both Rochester, then they are probably the same. At least "same enough" that they will swap out with no problem.

You might make sure they are both Rochester. Mercarb makes a carb that looks very similar. Quick and easy way to tell is the mixture screw(s). If memory serves, Rochester has two, while the Mercarb only has one.