Carburetors for 85 / 90 / 120 / 125 HP

[The Force power]

Do the numbers stamped in the carbs (where they bolt on the block) represent the HP or their appearance?
for example air/fuel mixture-screw external on the side V.S. on top inside at front ?

I'm trying to figure out if I just put a set of 120/125 Carbs on my 90HP

Also they spit fuel out of the air jets (mostly #1 & #2)

 

[roscoe]

There were a couple dozen different carbs used on those motor.

Find carb part number, like
tc119a
tc107a
tc138a

Jet sizes for a 3 cylinder motor with 3 carbs are .070, .074, etc.

Jets for a 4 cylinder with two carbs are larger, .092, .094, etc.

Id the carb, then verify the correct jet installed for your altitude.

you can sort through all the carbs, and the corresponding jets per altitude, on
the mercruiser parts dot com web site.

Note, the top/middle/bottom carbs are not necessarily the same, and the jets aren't either.

 

[jerryjerry05]

The 120 carbs are way bigger than the 90.

Spitting fuel out the air jets???
Fuel from the front is usually the reeds.
Fuel from the sides(carb) is usually the needle/seat or float not set right?

The #s on the carb are Tillitson or Walbro part #s
The only difference in the part #s on the carbs is the T fuel inlet.
The 2 bottom have a T the top has an L shaped fuel inlet.

The location of the air screws.

The 85 in the 80's has it in the top of the carb
Later years it moved to the side.
120/125 it was usually on the side.
The older was on the right side, later years it switched to the right.

 

[The Force power]

thank you Roscoe & Jerryjerry, Nordin

You guys are such a wealth of information; way better then the factory manual.

Yes the fuel is spitting out of the air-jets (I read about the front & reeds in other posts)

the reason I asked about the Carbs. I did not want to have a 125 carb. on a 90 as I don't know the harmfull affect