# Matching Carbs



## Sir Thomas (Dec 7, 2013)

I learned very quickly that not all carbs are alike. I know they vary slightly but I bid on a carb on ebay. It was a used one that looked in good shape. It was listed as a Carb from a Ryobi so I thought it would fix on the one I'm working on. Got it and installed it. The one thing I was concerned about wasn't an issue. The fuel inlet and outlet was where it needed to be. It was designed for a snap on primer which this trimmer had BUT the linkage was different. The old had the throttle plate on the top. The one I purchased was on the side and unless I did a lot of modification this wouldn't work. I tried firing it up without the throttle linkage connected. Wouldn't fire. In fact fuel was leaking out of the carb all over the place. So I took it apart to check it out. Apparently someone had cleaned it without blowing it dry. The whole carb felt like it was coated with laquer that hasn't dried. The diaphram gasket was glued on with the residue and in fact tore when I took it off. Luckly I had one that woud replace it and the diaphram. The metering valve was hanging up and the spring was in bad shape. Again, I had another good spring and I cleaned the metering valve and put it all back together. I mounted it on the Ryobi and cranked it. Turned once and then nothing. I knew there was nothing wrong with the Ryobi because I put a different carb from my personal trimmer and it worked. Then I got to looking at the carb closer....what! There is no choke on it so I put my finger on the inlet and pulled on it and it starting to fire. I kept my finger on it and cranked it and it ran good. Learn something everyday.


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## 30yearTech (Sep 14, 2006)

There are literally thousands of different carburetors and some may even look identical to each other. They are designed with emmission and displacement in mind for their specific application. 

Depending on the engine's displacement and fuel requirements the carburetor can have different jetting and venturi openings. So each carburetor (even though it may bolt right up), may not work properly on your specific application. Same is true for 4 cycle engines as well.


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## Sir Thomas (Dec 7, 2013)

30yearTech said:


> There are literally thousands of different carburetors and some may even look identical to each other. They are designed with emmission and displacement in mind for their specific application.
> 
> Depending on the engine's displacement and fuel requirements the carburetor can have different jetting and venturi openings. So each carburetor (even though it may bolt right up), may not work properly on your specific application. Same is true for 4 cycle engines as well.


That's why I'm trying to locate a used Walbro WYC-4-1 Carb for a Ryobi BC30 Trimmer I'm rebuilding. I know the unit works fine The original carb has a damage jet port which is fixed (not removable) I know the WYL's and others have a jet port that can be rebuilt with a new "O" ring. I tried removing it per instructions not realizing that in this carb, the jet port does not come out. I don't want to spend a lot of money on this machine.


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## 30yearTech (Sep 14, 2006)

The chances of getting a *GOOD* used carburetor are pretty slim. IMHO


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## Sir Thomas (Dec 7, 2013)

30yearTech said:


> The chances of getting a *GOOD* used carburetor are pretty slim. IMHO


I'm shopping for some junked equipment in the area. Scott, a friend, is bringing over some junk machines he has found.:

woohoo::woohoo: More toys to play with.


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