diaphragm vs. rotary carb

[gwtx]

What's the difference, and advantages/dis-advantages ?

 

[gwtx]

What's the difference, and advantages/dis-advantages ?

couldn't figure out how to edit the post,so,,,,
Some echo machines list a "rotary" carb, and some a " diaphragm" carb.
Just curious as to the differences, and or advantages/disadvantages.

 

[Rivets]

This website explains the differences better than I can. Basically the difference is the type of throttle valve used. Some say that you have better control with a rotary valve as compared to a butterfly valve. To each their own.

Carburetor - RC Wiki

 

[MowerMike]

They are the same thing. Than carb has a rubber diaphragm with a rotary valve throttle.

 

[gwtx]

Thanks for the replies. The "RC Wiki" site has a good explanation, thanks for the tip.

 

[reynoldston]

This is the first time I have heard of a rotary carburetor. It just looks like a different style throttle valve compared to a slide valve in a motorcycle type engine? I have worked on the diaphragm carburetors which are on a lot of 2 cycle engines which can operate in a up side down position like chainsaws, trimmers, snowmobiles. The ones I have worked on have a built in fuel pump and the diaphragm works the needle valve. All the lawn mower engines all seem to have a float in which the engine operates in a level position. Just where is this rotary carburetor used, it said in small off road engines like in what?

 

[MowerMike]

Diaphragm carbs are used in situations where the fuel tank is below the carb and gravity feed to a fuel float bowl cannot be used. They can have either butterfly or rotary valve throttles, but are all diaphragm type carbs. The diaphragm serves the function of a fuel pump. They can be used in either two cycle or four cycle engines, which need to be used in difference orientations such as chain saws, string trimmers and blowers. The carb used in my Echo PB-250LN hand held blower is a Zama RB-K106, which is a diaphragm type carb with a rotary valve throttle. The letter "R" in the Zama p/n stands for rotary.

USA Zama : Products

 

[gwtx]

This is the first time I have heard of a rotary carburetor. It just looks like a different style throttle valve compared to a slide valve in a motorcycle type engine? I have worked on the diaphragm carburetors which are on a lot of 2 cycle engines which can operate in a up side down position like chainsaws, trimmers, snowmobiles. The ones I have worked on have a built in fuel pump and the diaphragm works the needle valve. All the lawn mower engines all seem to have a float in which the engine operates in a level position. Just where is this rotary carburetor used, it said in small off road engines like in what?

My poulan pro link system powerhead has a "rotary" carb. It's a "Ruixing" which seems to be finding their way onto more and more engines. Another chinese carb. Looks pretty good, no kits available, but walbro metering diaphragms will work, maybe some other K10 kit parts too.