View Full Version : 2 cycle wt carburator air leak problem


willie
03-16-2009, 09:55 PM
HI!! My name is Fred. I am a retired carpenter of 54 yrs.I live in Bay City,Tx. That is about 80 miles SW of Houston,Tx. I have a small repair &
saw sharpening shop next to my home. I have worked on 2 &4 cycle engines in the past with mostly good results.
This is my first thread. Hellllllppp!!! This(WT 324 Carb.) chainsaw is not starting + air bubbles & gas are coming out of carb. to the primer bulb. I overhauled the carb. by cleaning passages , new welch plugs, carb. kit, air +
gas filters, primer bulb & gas lines.I put new gas in tank but same problem!!
Hellllllppp!!! The gas from tank to carb. is solid gas. The air bubbles & gas are
still coming from carb. to primer bulb. no matter how many times I pump the bulb.(1 to 40 times) Installed new spark plug & checked for spark to plug
Good spark! Could the main nozzle check valve causing air bubbles? It is brass
& looks pressed into the carb. I have not checked muffler for carbon blockage or scored cyclinder but will. Compression is good.
Thanks,fwilliams979

harmocy
03-16-2009, 10:02 PM
When you say you cleaned the carb did you soak it??? this is critical because especially in a small carb like this the smallest ammount of blockage even thoughg you can blow through it may cause a problem the best way i have found is to goto the autoparts store and get a boil which is a 1 gal can that has a dip basket in it and remove any rubber componets from carb and soak over night this has worked for me in the past

willie
03-16-2009, 10:46 PM
Soaking over night ? Will that make the plastic parts in carb. deteriorate?
I always use carb. spray cleaner & blow it out. The chainsaw was runing
2 weeks ago with new gas & just died. It's has not been sitting idle.
Thanks, willie

30yearTech
03-17-2009, 12:29 AM
Soaking over night ? Will that make the plastic parts in carb. deteriorate?
I always use carb. spray cleaner & blow it out. The chainsaw was runing
2 weeks ago with new gas & just died. It's has not been sitting idle.
Thanks, willie

Hi, Fred and welcome to hobbytalk, hopefully we will be able to help some.

It's not advisable to soak these types of carburetors or to use carburetor dip at all. The air bubbles can be coming from a leaking high speed check valve and dipping a carburetor can destroy these check valves. Little bubbles in the fuel line from the carburetor to the primer should not prevent the engine from starting, but if the check valve will not seal when the engine is running, that could cause an issue.

Other then the little bubbles in the fuel hose when primed, what other issues are you having?

Does it start and not run, or will it not start at all?

What is the brand and model number of whatever it is your working on?

willie
03-17-2009, 08:00 PM
The poulan 2075 16" chainsaw will not start at all. I took the muffler off &
cleaned it & the screen. The cyclinder looked good.


AMENDMENT:
The air bubbles have almost vanished. I read an earler thread you had that
said any (PINK COLOR) needle valve tip is bad. The (GRAFITE COLOR) needle vavle tip is not worn & is good. I put the pink one back into carburator thinking it was new & the grafite one was bad. I forgot which one was the new one out of new kit.
I never knew before that change in color (pink) of needle tip is a sign of
worn tip, that it might stick to the seat & cause problems.


So much for my mistakes.

Thanks for all the help, willie


PS: Now for the no start at all problem. WT-324

Carburator has been cleaned,sprayed,blown out,new welch plugs,carb.kit,
gas lines,air&gas filters,primmer bulb&new spark plug.

Pulled muffler,cleaned & checked cylinder. Good shape. Good compression.
Fire to spark plug.

Primed,chocked & pulled rope 4-6 times. Did not atemp to start.
Again & again - NO START.

I pulled supply gas line off carb.inlet(pump side) from tank filter. The gas keeps comming out like it is pressured up in tank, untill the tank cap is unscrewed. Where did I mess-up on my carb. overhall!!!

The spark plug is dry. HELLLP!!!!!!


THANKS AGAIN, willie

virtdave
03-17-2009, 09:33 PM
I'm joining this thread because I've got a very similar problem--if indicated, can of course start a new thread.
I have a Tanaka 425TBC weedeater, with a Walbro HDA44 carb. It does start, but at high speed, dies unless I choke it about halfway, so I guess it's running lean. I completely rebuilt the carb, including removing the Welch plug covering the idle holes pocket, over the (three) idle holes, and the plug over the high-speed jet. On this model, there's no high-speed check valve as such, a screen serves this purpose. I did not soak the carb once dis-assembled, but cleaned the passages with carb spray and blew them out with compressed air, and am pretty sure there's nothing blocking any of the passages.
Willie, I assume you tried squirting a little gas into the carb throat and tried starting? Also, if it's a Walbro, there's a tool to pop out the main nozzle check valve (which obviously I did not need, given the above).

jsouth
03-19-2009, 12:31 PM
Can some one show me a picture of the main nozzle check valve,and how to remove it.I have remove the screen and the metering lever and the needle many times and replaced the carb. kits with new ones.Ya'll talk about the main nozzle in this thread I use only carb. spray to clean the carbs.

Thanks
Jerry

30yearTech
03-24-2009, 09:16 PM
Can some one show me a picture of the main nozzle check valve,and how to remove it.I have remove the screen and the metering lever and the needle many times and replaced the carb. kits with new ones.Ya'll talk about the main nozzle in this thread I use only carb. spray to clean the carbs.

Thanks
Jerry

On many carburetors they are not replaceable, on some they are under a welch plug, others they are a complete assembly that is driven through into the throat of the carburetor from the metering side, and then tapped back into place, still some require special tools to remove. Sorry I don't have any pictures, but if you log onto the Walbro or Zama site you may be able to locate some illustrations.

Cmarti
03-25-2009, 08:56 AM
http://www.drystacked.com/Walbro%20Carburetor%20Theory%20ebook1.pdf

Pretty good info and photos. I do not think the check valve is replaceable, but I do not think a few fine air bubles in the plunger is fatal.

Good luck

jsouth
03-26-2009, 07:11 PM
Thanks 30yearTECH and Cmarti for the info.

Jerry