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carburetor or mixer, whats the difference?

DustyBar

Subscriber
Last Subscription Date
01/14/2020
The title basically describes my question. Is the only difference that a carburetor has a float to maintain fuel level in a fuel bowl? I've seen mixers that had a fuel bowl too but with an overflow and return line to maintain the level.
 

stufforbud

Subscriber
Last Subscription Date
09/17/2019
Just to keep it simple a mixer just makes a combustible mixture available to an engine that is speed governed by another method, where a carburetor is required to do both functions, ie. deliver a mixture and govern speed by the butterfly position.
 

KeithW

Subscriber
Age
65
Last Subscription Date
02/28/2020
I have seen carbs that have no throttle plate. Exactly the same as a carb with one but the holes for the shaft were never drilled. Not sure of the application. I think it might have been on some kind of heater.
 

Doug Tallman

Subscriber
Last Subscription Date
10/11/2019
The Tillotson carb used on the Briggs PB were made with or without the throttle plate. Same carb otherwise. Maybe more that a carb has an idle and main circuit and a mixer only has one?
 

edisondiamond

Registered
The mixers I have been around are what I would call a drip carb. The fuel is turned on, and a metering needle adjusted for flow. Like on the single cylinder type engines used on a drag saw. No butterflys.
 

TekNik

Registered
Do IH M engines have a carb or a mixer?
There is a throttle plate to control speed and a bowl, but no float.
I call them carbs because they are more complex than a one needle mixer.
What do you think?

TekNik
 

Tom Stockton

Member
Age
66
Last Subscription Date
01/30/2020
I've wondered about this issue before, & did a little research.
Dictionaries don't address it.
Wikipedia (while informative) didn't settle it either.

So I'm going by popular usage....
Carburetor:
A device for mixing liquid fuel & air in the proper ratios & amounts.

Mixer:
A primitive type of carburetor which doesn't have a float to regulate fuel flow.
 

JoeCB

Subscriber
Last Subscription Date
03/19/2020
Just to keep it simple a mixer just makes a combustible mixture available to an engine that is speed governed by another method, where a carburetor is required to do both functions, ie. deliver a mixture and govern speed by the butterfly position.
I think that the key difference for a mixer is in this …"to an engine that is speed governed by another method".

Joe B
 

Andrew Mackey

Moderator
Last Subscription Date
05/14/2017
A mixer is just that - it mixes liquid gasoline with air. Most mixers are crude, and they end up with liquid gas driping out of the intake. most hit and miss engines use mixers. There are no throttles and some even have to use a partial choke or 'snifter valve' to draw fuel properly. Most do not have venturi (an internal air flow restriction) to operate.

A carburetor operates on a slightly different principle. It breaks gasoline into small particals to help with vaporixing the gasoline or other liquid fuel. it uses venturi to create a low pressure area to draw and mix fuel and air better. Most but not all use a throttle plate. A carburetor does not have to have a throttle plate. it can be located further down stream on the intake. that is exactly the case with the IHC M. The throttle on the M is atually in the head, below the carburetor. Fuel level is maintained by an overflow dam in the carb body. The overflow carburetor was used on other engines and in some cars as well. On the M carbs, the venturi is located between the carb upper and lower sections, and is made of zinc. If it is eroded or missing, the carb will not function properly, if at all.

Carbs are much more effeceint than mixers. When throttled engines came out, mixers were all but eliminated, just as fuel injection now has virtually eliminated carbs today. The finer you can vaporize a fuel, the better and more complete the combustion. Believe it or not, back in the early 1900s there were several devices that actually wicked gas up on a mantle, and the engine sucked the vapor into the intake instead of liquid fuel. Great idea but not too practical - trying to regulate the amount of vapor needed for a power setting was problematic. Too much the engine flooded, too lean and a backfire would set the mantle alight.:eek: The idea didn't last long!
 

John Davis

Subscriber
Age
58
Last Subscription Date
03/14/2020
Just to keep it simple a mixer just makes a combustible mixture available to an engine that is speed governed by another method, where a carburetor is required to do both functions, ie. deliver a mixture and govern speed by the butterfly position.
There are mixers that also do both functions, combustible mixture & speed control. Not all engines with mixers or carb's are speed governed. Most early inboard marine engines are not speed governed. On most early inboard marine engines the speed is controlled manually by a throttle mechanism on the mixer or carb. Speed could also be controlled manually to a certain extend by the ignition timer.
 

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