Walbro Carbs

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257 is the basic carb. 644 has a gas priming bulb on the top. 1027 is the big bore carb. Not sure what the bore is. Most run the 257. I have several with different bores. Also have knife blade mods done to shaft and butterfly.
Mike
 
257 is the basic carb. 644 has a gas priming bulb on the top. 1027 is the big bore carb. Not sure what the bore is. Most run the 257. I have several with different bores. Also have knife blade mods done to shaft and butterfly.
Mike

The 257 and the 1027 are the same carb. 1027 just denotes it was made/sold for/through Zenoah. This is why is was quickly added to list of acceptable carbs for stock classes.
The 1048 has larger venturi. All have similar bore.
 
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Good to know. I saw it some where calling it a big bore carb. Cant for the life of me remember where. Maybe they just ment big venturi.
 
Most all of the WT Walbros that we use on gas boats have a .625" throttle bore, and a .500" (12.7mm.) venturi ( 257, 644, 929, 771, ect. ). It became very popular and easy to bore out and blend the venturi larger. Most thought that their motors needed more flow from the carb, and it is a money maker. They look really sexy when the air entry is mirror polished ( hey, it sells! ). Walbro took notice and decided to offer a "factory big bore". Not as pretty as the "modified carbs", but they made the venturi 13.5mm and kept the throttle at the same .625". They called it the "Big Bore" 1048. It takes an extremely strong flowing motor to require more than a stock gas carb.
 
Hi Dennis,

Can I ask you maybe; I have a WYK33 with 15 mm throttle bore and 13,5 mm venturi in box.

Is this fit there for Mod 26 cc Zenoah instead of Mod 257 ? (I have now on this)

Joseph
 
Joseph there are Walbro WYK33s and there are clones of the same. The "real" ones have a black colored high needle screw, and the clones are brass. They will both work OK on most gas motors. They do require an external pulse line to be connected from the case/cyld. in order to operate the internal fuel pump. The 257 (and most other WTs) use a hole in the manifold to do the same. These barrel carbs flow well, but again, don't expect any silver bullet.
 
Hi Dennis,

I have a clone.
Is there any adapter available to Zenoah and maybe a compact throttle arm?

Thanks
 
One of the best linkages for those carbs is from Accutech. It's made for QDs using those carbs, but works for other engines as well. The part # is QDTL-100, and sells for $22. Accu-Tech RC Hardware Accessories

You may have to do a search for a manifold as I don't bother much with 33s or with Zens, so I'm not familiar. I do know they are out there; perhaps overseas.
 
The throttle won't work for a wyk on a Zenoah unless you first install a straight pull intake with carb bolts at 6 and 12 o'clock.

There are intakes that will bolt up a wyk like it needs and even ones that will supply pulse internally.
 
Thanks again Dennis.

Hi Daniel,

Thanks for the input

There are intakes that will bolt up a wyk like it needs and even ones that will supply pulse internally.

That intake what I'm looking for, if the level of supplied pulse enough from there
 
G'day Dennis..

What carby kit can i buy for my pair of walboro 1048 carbies for nitro use? Or can i use standard seals etc..
 
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