Carb Size
 

Ok please no one shoot me but I was wondering if we could get a discussion started reguarding carb sizes on engine conversions. I like to hear from people who have tried different size carbs on different size engines and does increasing the throat size make that much difference. I have a few carbs with even amounts of small and larger throats and not sure which I will use. The engines Im wondering about range from 30cc to 45-50cc but not any one brand specificly. Just curious as to what others have come up with ??????

RE: Carb Size
 

Let me know what engines you have, and the carbs you have on hand or can get easy. Then I can try and help you out. Capt,n

RE: Carb Size
 

The engines I have are as follows (all homelites) 30cc(wacker), 33cc(chainsaw), 45cc(chainsaw) and a few 31cc ryobi twin rings. I have the stock carbs both small and large opening and also have a WT324. what Im wondering is if it is worth shopping around for just the right carb or will the ones that come with the engines be enough. I know with full size cars you can over carb something real easy. Thats what I dont want to do. If you have specific carbs numbers, great! Ill look for those, if its just throat size it will help me as well. I cant say whay a help this web site has been to me! Thank You Kindly for any answers in advance.

RE: Carb Size
 

You will need bigger carbs for air craft use if you want any kind of performance. You can overcarb a car but you will still get alot of performance from it and as long as you can ignite and burn the fuel well you would have gain some reliablity also. Cars don't deel with rapid changes in altitude and fast g forces like an aircraft and this is why a bigger carb with better pumps on them work well on aircraft. Aircraft engines are more reliable also for lots of reasons one being cooler temps and less loads their is no gear box or wheels to turn on a hard surface. Walbro WA-164 is a good carb for your 25cc's through 32cc's anything above that I have no experience with but you can the the walbro web site for the size zenoa use on there model engines as reference. Good Luck.

RE: Carb Size
 

heres what i have and these work fine.i read somewhere that the number on the intake,under the choke means somthing like the venturi is half that number in mm.dont know if this is true or not.i was told you want at least 11mm venturi.
the numbers im giving you are carb and the number on intake opening.
poulan33cc--carb--wa19---throat 27
ryobi31cc--carb--wa199--throat 18--changing to 20
quadra35cc--wa00--throat28
echo21or22cc--wa199--throat18.--leaving as is.
hope this helps some. i dont look at 100s of numbers.i use a 6.99 steel slide micrometer and measure the results with a ruler that has inches and mm on both sides.

RE: Carb Size
 

This data may help in your general understanding of Walbro carbs.
http://www.walbro.com/pdf/DiaphragmCarb.pdf

browng300
Found the 164 at their site but the screen I got did not show venturi size. Do you happen to know what it measures?

Walbro venturi size markings: "If there are two raised numbers on the face of the venturi, that is the throat size in 64 ths of an inch." per Flypaper 2

RE: Carb Size
 

What I am getting from this is that I need a carb with a throat size of 11mm or just a bit bigger. I have a link here and I dont know if this will work but this is where I go to find specs on some of the carbs I have.
[link]http://wem.walbro.com/walbro/family2.asp[/link] If that worked right you will find a screen with letters on it. Click on the letters of the carb you have, next page will be carb numbers, click on that and you should see the specs as well as part numbers for replacement parts. Thanks for everyones feedback on this and I hope that what I typed helped as well.

RE: Carb Size
 

WA-167 is the number, I am so sorry TypeO and it is a 11.mm ventrui, works real well.

RE: Carb Size
 

ALW Phantom
If the 45 has a Walbro, it will probably be stamped with a 32 for 32/64 and would have 12.7mm venturi.

RE: Carb Size
 

The WA199 have a 7.94mm venturi and the WA19 has an 11.13mm venturi. The WA167 is what is stock on the Zenoah G23, it has an 11.11 venturi. I bought a WA167 from Horizonhobby for my converted 25cc Homey. I couldn't get it started with an electric started, battery was a little down. but I wrapped small diameter rope around the prop shaft and it cranked right up. had to reset the low end back to 1 1/2 turns out and lean it about 1/8 turn on the low end. Haven't used a tack on it yet, its going in a 120 Stinger.

The WA00 maybe you misread the numbers, its not on my reference chart.

will

RE: Carb Size
 

Hi I am in need of a walbro carb for a A&M 2.0 . I was told that a wt76 will work fine . Maybe I can find one here RCU to start with . Now on some of these carb the throttle shaft is at diffrent locations on the carb . Is there a letter for that also? But any way I am in need of a carb . Thanks PHD

RE: Carb Size
 

Walbros are almost all the same relative to throttle shaft, except for the WTA6 used on the older G38..It is a mirror image, with the throttle shaft at a different angle...There are only 2 different mounting bolt patterns on all Walbros...The throttle shafts will have different steel end shapes....

RE: Carb Size
 

mikenlapaz,
When viewing the specs on the Walbro website as ALW Phantom instructed, if you don't see the venturi size, click on the link just above the spec chart that says "click here for a printer friendly version". A new window will pop up with the specs and the venturi size should be listed at the top of the new spec sheet.

Gary

RE: Carb Size
 

gtisme
:D:D Neat tip , thanks for sharing :D