Walbro Carburator Rebuild

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  #1  
Old 05-20-09, 08:19 PM
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Walbro Carburator Rebuild

Hi all,

I have a Craftsman 16" chainsaw (358.352161) that won't start. (I'll tell the whole story if my to-be-rebuilt carb does not work for me.) After checking various items I decided to rebuild my carburator. The carb is WT-324 and for that I bought a repair kit called K10-WAT. First thing I found was that the kit came with over-supplied parts/gaskets that I don't need (or do i?). I took care of the easy ones -- the membranes, the gaskets, and the needle. But I got some one tiny screen, two little alum caps, and one c-shape open ring that I don't know what to do with. Searching the forum and I came across the follow by a fine gentleman:

"Take the pump side of the carb. off you will find a little screen take care to remove it and put it on a paper towel and use a eye dropper with a drop of water to see if water will go through the screen,I have a lot of carbs that have a clog screen.Hope this helps."

I think he is actually refering to these little parts I am talking about. I did find two circular holes on the pump side with caps that potentially can be the replacement cadidates, but I don't see how to extract them. Can anybody please help explain how I should fit these little parts into my to-be-rebuilt carb? Thanks!

Shay
 
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  #2  
Old 05-20-09, 08:29 PM
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OK the plugs are pressed in. Behind them is the butterfly valve stem. So do not replace them. Also the screen is needed. They often get lost while taking the carb apart. Yes you will have lots of left over parts. The kits are made to service many different carbs. Just replace the needle, gaskets, diaphragm, screen (no need to check it, just replace it). The tiny screw is for the barrel/butterfly valve. Caps are for the valve stem/shaft. The "C" clip is for the valve shaft. Hope that helps
 
  #3  
Old 05-20-09, 09:05 PM
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Don't quite get it

Re: reply from Mr vender

*******()
OK the plugs are pressed in.

Behind them is the butterfly valve stem. So do not replace them.

Also the screen is needed. (which screens, where do they go?)
********()
They often get lost while taking the carb apart.

Yes you will have lots of left over parts.

The kits are made to service many different carbs.
Just replace the needle, gaskets, diaphragm, screen (no need to check it, just replace it).

********()

The tiny screw is for the barrel/butterfly valve. (did not find a screw in kit)

Caps are for the valve stem/shaft.

The "C" clip is for the valve shaft. ()

*******

Hope that helps

*******


Thanks anyway for trying to help me! Hope I can get some clarification (clearly I'm not smart enough).

Shay
 
  #4  
Old 05-20-09, 09:31 PM
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Hello Shay,

Generally, you can replace the parts that are obvious and easy to replace and call it a done deal. Most times the caps you see don't have to be removed. The C ring either. Hang on to the parts until it's running right though, just in case further dismantling of the carb is necessary.

Clean all passages, replace the diaphragms and gaskets, replace the needle and the arm that holds the needle, and replace the screen. On your carb, there should be a round opening under the cover that has the fuel pump diaphragm (the flat one with the 2 flaps...the one without the round metal disk on it). There should be a screen pushed down into this opening. If there isn't, it is missing. This is where you put the new screen. Push it down into the round hole until it seats on the bottom and that's all there is to it. Use a blunt end of a small drill bit to help guide it and seat it into the hole.
 
  #5  
Old 05-21-09, 03:44 AM
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Two little caps in the carburator

Cheese,

I did everything you mentioned the first time around, and you guessed it, the chainsaw did not get fixed (actually it started and run for a minutes and then it would not start again after I shut it off).

Since I did not take care of the two little caps during the rebuiling process, I really like to learn what their purpose are. On top I came across this tips about "pump-side screen" from my base note. I did not notice a screen on the pump side (i.e. the needle side). Can anyone elaborate what those caps are and what's under those caps (they are also located on the "pump side")

Thanks!

Shay
 
  #6  
Old 05-22-09, 12:51 AM
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I never have to remove them. I don't recommend removing them except as a last resort because getting the new ones in to stay may prove to be quite a chore. Is the engine not getting enough fuel, or too much? Can you add some fuel to the cylinder and get it to start? Have you made any adjustments to the carb, and if so, what are the current mixture screw settings? Did you blow out all passages with compressed air?
 
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Old 05-22-09, 04:39 AM
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  #8  
Old 05-23-09, 10:52 PM
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Finishing my homework..

Cheese,

No I have not gone thro all the steps you mentioned. I'll do it this weekend and hopefully have something to report back. Thanks for the suggestions. Have a good holiday!

Shay
 
  #9  
Old 05-25-09, 09:49 AM
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Fuel cap functional check

One side question for my chainsaw that won't start:

How do you check if a fuel cap is functioning properly?

I guess the two major functions are:

1. prevent fuel from leaking out

2. allow the fuel tank to "breath in"

My cap definitely has Prob 1 before I took it aprat and fix it. After the fix, the fuel does not seep out anymore. But how do I know the check-valve feature allows the fuel tank to breath?

Let us say if the cap's breath hole were indeed completely clogged. Would the engine typically start at all? If answer is yes, how long does it usually take for the idle engine to stall when the vacuum in the tank build up?

Answers to ALL my questions are appreciated.

Shay
 
  #10  
Old 05-25-09, 11:01 AM
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A plugged cap is not likely to prevent it from starting and may not keep it from running however it may act and actually run lean or starving for fuel which is not good since it will run hotter and not receive sufficient lubrication.
Usually it will cause it to die eventually but the amount of time it takes all depends on the size of the tank, amount of fuel in the tank, temperature, engine condition...etc.
If the fuel cap is the problem it should be repeatable and diagnosed if when the gas cap is removed and replaced, it restarts and repeats.

 
  #11  
Old 05-28-09, 09:38 PM
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how to add fuel to cylinder

What are the best ways to "add some fuel to the cylinder" to see if my engine would fire. I look around my garage and could not find anything (applicator) that allowed me to shoot a jet of gasoline into the engine chamber through the throat of the carb..

(Just a reminder: I do have sparks)

I tried spraying some WD40 fluid and later some carb cleaner fluid and did not get the engine to firing, but that was kind of expected.

Does the fuel gets sent into the engine chamber need to be in some sort of misty form? How much amount would be optimal?

Shay
 
  #12  
Old 05-28-09, 09:44 PM
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Take the spark plug out, drop a teaspoon of fuel into the plug hole, put the plug back in and try to crank it up.
 
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