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Walbro 2-cycle carb model number + letter

Posted by mustangm 10 (My Page) on
Tue, Jun 25, 13 at 21:26

I just pulled a Walbro WT-326C 2-cycle carb off my neighbor's non-working Stihl 020T chainsaw and have two quick questions.

First, what does the letter 'C' indicate at the end of the model number? I can find no data about this model WT-326C, but I can find info on WT-326 and WT-326-1.

Second, this carb only has only one adjustment needle. There are 2 holes labeled H and L, but one of these is plugged up. So is this the HIGH or LOW adjustment needle? Or is it some combination HIGH/LOW adjustment. I have not been able to find any information on a single needle 2-cycle carb so it is a bit perplexing to me.

Thanks for the help and advice!

Follow-Up Postings:

RE: Walbro 2-cycle carb model number + letter

I had single needle Walbro WT carbs on a couple of hand held blowers. Choke plates only, no throttle.The carb you have is rare. The C possibly indicates it is used in a chainsaw application. Some single needle carbs by Walbro do not have a Main Nozzle. They only have a fuel port in the venturi of the carb that flows fuel The single needle was used to adjust the air mixture at Low speeds I think.` Your needle is in the left side in the L hole, right? That carb is supposed to have 2 mixture needles in it.

RE: Walbro 2-cycle carb model number + letter

Is it possible the other needle is broken off in the hole?

RE: Walbro 2-cycle carb model number + letter

Here is a pic of the carb. I have it apart so the needle is out, but you can see there is a L and H marking and the needle that was there is in the L slot. Weird that the H slot hole is larger than the L hole, but maybe that is normal. This carb has both a choke plate on one side and throttle plat on the other.

So can I assume that there is no high speed adjustments that can be made to this carb? I adjust the low and the idle and that is the best I can do?

I have a new gasket kit and it contains a blue gasket that matches the one I have. I will post my question about it on a new post. Thanks

RE: Walbro 2-cycle carb model number + letter

You may find that adjusting the lone LOW side needle will affect the engine at all speeds. The main nozzle (if there is one) output is a culmination of adjusting the L and H mixture screws. Here is an instructional link to the Walbro WT chainsaw carburetor. I notice they only list WT-326-1. The blue gasket in the kit you have is the fuel pump for the carb. It is made of mylar. The tan one is teflon and the black one would be of a rubber composite.

This post was edited by homegrown55 on Thu, Jun 27, 13 at 12:42

RE: Walbro 2-cycle carb model number + letter

I can answer one question for you. Tecumseh also used the Walbro (WT & WTA) carburetors on their TC300 engines,The screw is for low, which adjusts the idle mixture. To preset thread in all the way finger tight. Then screw out to 1- 1 1/8 turns out. After starting the engine and letting it warm up 3-5 minutes turn the screw clockwise until the RPM just starts to decrease. Stop and note the screw position. Then turn slowly counter-clockwise. The engine RPM will increase to a point then start decreasing. Stop at this point and note position. To finish setting turn the idle mixture screw halfway between those two points. It's now set.

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